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<book>

<bookinfo>
<title>The Mutt E-Mail Client</title>
<author>
<firstname>Michael</firstname><surname>Elkins</surname>
<email>me@cs.hmc.edu</email>
</author>
<releaseinfo>version @VERSION@</releaseinfo>

<abstract>
<para>
<quote>All mail clients suck.  This one just sucks less.</quote> &mdash;
me, circa 1995
</para>
</abstract>
</bookinfo>

<chapter id="intro">
<title>Introduction</title>

<para>
<emphasis role="bold">Mutt</emphasis> is a small but very powerful
text-based MIME mail client.  Mutt is highly configurable, and is well
suited to the mail power user with advanced features like key bindings,
keyboard macros, mail threading, regular expression searches and a
powerful pattern matching language for selecting groups of messages.
</para>

<sect1 id="homepage">
<title>Mutt Home Page</title>

<para>
The official homepage can be found at
<ulink url="http://www.mutt.org/">http://www.mutt.org/</ulink>.
</para>

</sect1>

<sect1 id="muttlists">
<title>Mailing Lists</title>

<para>
To subscribe to one of the following mailing lists, send a message with
the word <emphasis>subscribe</emphasis> in the body to
<emphasis>list-name</emphasis><literal>-request@mutt.org</literal>.
</para>

<itemizedlist>
<listitem>

<para>
<email>mutt-announce-request@mutt.org</email> &mdash; low traffic list for
announcements
</para>
</listitem>
<listitem>

<para>
<email>mutt-users-request@mutt.org</email> &mdash; help, bug reports and
feature requests
</para>
</listitem>
<listitem>

<para>
<email>mutt-dev-request@mutt.org</email> &mdash; development mailing list
</para>
</listitem>

</itemizedlist>

<para>
All messages posted to <emphasis>mutt-announce</emphasis> are
automatically forwarded to <emphasis>mutt-users</emphasis>, so you do
not need to be subscribed to both lists.
</para>

</sect1>

<sect1 id="distribution">
<title>Getting Mutt</title>

<para>
Mutt releases can be downloaded from <ulink
url="ftp://ftp.mutt.org/pub/mutt/">ftp://ftp.mutt.org/pub/mutt/</ulink>.  For a
list of mirror sites, please refer to <ulink
url="http://www.mutt.org/download.html">http://www.mutt.org/download.html</ulink>.
</para>

<para>
For version control access, please refer to the
<ulink url="https://gitlab.com/muttmua/mutt">Mutt development site</ulink>.
</para>

</sect1>

<sect1 id="irc">
<title>Mutt Online Resources</title>

<variablelist>

<varlistentry>
<term>Bug Tracking System</term>
<listitem>
<para>
The official Mutt bug tracking system can be found at
<ulink url="https://gitlab.com/muttmua/mutt/issues">https://gitlab.com/muttmua/mutt/issues</ulink>
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>Wiki</term>
<listitem>
<para>
An (unofficial) wiki can be found
at <ulink url="https://gitlab.com/muttmua/mutt/wikis/home">https://gitlab.com/muttmua/mutt/wikis/home</ulink>.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>IRC</term>
<listitem>
<para>
For the IRC user community, visit channel <emphasis>#mutt</emphasis> on
<ulink url="http://www.freenode.net/">irc.freenode.net</ulink>.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>USENET</term>
<listitem>
<para>
For USENET, see the newsgroup <ulink url="news:comp.mail.mutt">comp.mail.mutt</ulink>.
</para>
</listitem>
</varlistentry>

</variablelist>

</sect1>

<sect1 id="contrib">
<title>Contributing to Mutt</title>

<para>
There are various ways to contribute to the Mutt project.
</para>

<para>
Especially for new users it may be helpful to meet other new and
experienced users to chat about Mutt, talk about problems and share
tricks.
</para>

<para>
Since translations of Mutt into other languages are highly appreciated,
the Mutt developers always look for skilled translators that help
improve and continue to maintain stale translations.
</para>

<para>
For contributing code patches for new features and bug fixes, please
refer to the developer pages at
<ulink url="https://gitlab.com/muttmua/mutt">https://gitlab.com/muttmua/mutt</ulink> for more details.
</para>

</sect1>

<sect1 id="typo">
<title>Typographical Conventions</title>

<para>
This section lists typographical conventions followed throughout this
manual. See table <xref linkend="tab-typo"/> for typographical
conventions for special terms.
</para>

<table id="tab-typo">
<title>Typographical conventions for special terms</title>
<tgroup cols="2">
<thead>
<row><entry>Item</entry><entry>Refers to...</entry></row>
</thead>
<tbody>
<row><entry><literal>printf(3)</literal></entry><entry>UNIX manual pages, execute <literal>man 3 printf</literal></entry></row>
<row><entry><literal>&lt;PageUp&gt;</literal></entry><entry>named keys</entry></row>
<row><entry><literal>&lt;create-alias&gt;</literal></entry><entry>named Mutt function</entry></row>
<row><entry><literal>^G</literal></entry><entry>Control+G key combination</entry></row>
<row><entry>$mail_check</entry><entry>Mutt configuration option</entry></row>
<row><entry><literal>$HOME</literal></entry><entry>environment variable</entry></row>
</tbody>
</tgroup>
</table>

<para>
Examples are presented as:
</para>

<screen>
mutt -v
</screen>

<para>
Within command synopsis, curly brackets (<quote>{}</quote>) denote a set
of options of which one is mandatory, square brackets
(<quote>[]</quote>) denote optional arguments, three dots
denote that the argument may be repeated arbitrary times.
</para>

</sect1>

<sect1 id="copyright">
<title>Copyright</title>

<para>
Mutt is Copyright &copy; 1996-2021 Michael R. Elkins
<email>me@mutt.org</email> and others.
</para>

<para>
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
</para>

<para>
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.
</para>

<para>
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
</para>

</sect1>

</chapter>

<chapter id="gettingstarted">
<title>Getting Started</title>

<para>
This section is intended as a brief overview of how to use Mutt.  There
are many other features which are described elsewhere in the manual.
There is even more information available in the Mutt FAQ and various web
pages. See the <ulink url="http://www.mutt.org/">Mutt homepage</ulink>
for more details.
</para>

<para>
The keybindings described in this section are the defaults as
distributed.  Your local system administrator may have altered the
defaults for your site.  You can always type <quote>?</quote> in any
menu to display the current bindings.
</para>

<para>
The first thing you need to do is invoke Mutt, simply by typing
<literal>mutt</literal> at the command line.  There are various
command-line options, see either the Mutt man page or the <link
linkend="commandline">reference</link>.
</para>

<sect1 id="core-concepts">
<title>Core Concepts</title>

<para>
Mutt is a text-based application which interacts with users through
different menus which are mostly line-/entry-based or page-based. A
line-based menu is the so-called <quote>index</quote> menu (listing all
messages of the currently opened folder) or the <quote>alias</quote>
menu (allowing you to select recipients from a list). Examples for
page-based menus are the <quote>pager</quote> (showing one message at a
time) or the <quote>help</quote> menu listing all available key
bindings.
</para>

<para>
The user interface consists of a context sensitive help line at the top,
the menu's contents followed by a context sensitive status line and
finally the command line. The command line is used to display
informational and error messages as well as for prompts and for entering
interactive commands.
</para>

<para>
Mutt is configured through variables which, if the user wants to
permanently use a non-default value, are written to configuration
files. Mutt supports a rich config file syntax to make even complex
configuration files readable and commentable.
</para>

<para>
Because Mutt allows for customizing almost all key bindings, there are
so-called <quote>functions</quote> which can be executed manually (using
the command line) or in macros. Macros allow the user to bind a sequence
of commands to a single key or a short key sequence instead of repeating
a sequence of actions over and over.
</para>

<para>
Many commands (such as saving or copying a message to another folder)
can be applied to a single message or a set of messages (so-called
<quote>tagged</quote> messages). To help selecting messages, Mutt
provides a rich set of message patterns (such as recipients, sender,
body contents, date sent/received, etc.) which can be combined into
complex expressions using the boolean <emphasis>and</emphasis> and
<emphasis>or</emphasis> operations as well as negating. These patterns
can also be used to (for example) search for messages or to limit the
index to show only matching messages.
</para>

<para>
Mutt supports a <quote>hook</quote> concept which allows the user to
execute arbitrary configuration commands and functions in certain
situations such as entering a folder, starting a new message or replying
to an existing one. These hooks can be used to highly customize Mutt's
behavior including managing multiple identities, customizing the
display for a folder or even implementing auto-archiving based on a
per-folder basis and much more.
</para>

<para>
Besides an interactive mode, Mutt can also be used as a command-line
tool to send messages. It also supports a
<literal>mailx(1)</literal>-compatible interface, see <xref
linkend="tab-commandline-options"/> for a complete list of command-line
options.
</para>

</sect1>

<sect1 id="concept-screens-and-menus">
<title>Screens and Menus</title>

<sect2 id="intro-index">
<title>Index</title>

<para>
The index is the screen that you usually see first when you start
Mutt. It gives an overview over your emails in the currently opened
mailbox. By default, this is your system mailbox.  The information you
see in the index is a list of emails, each with its number on the left,
its flags (new email, important email, email that has been forwarded or
replied to, tagged email, ...), the date when email was sent, its
sender, the email size, and the subject. Additionally, the index also
shows thread hierarchies: when you reply to an email, and the other
person replies back, you can see the other person's email in a
"sub-tree" below.  This is especially useful for personal email between
a group of people or when you've subscribed to mailing lists.
</para>

</sect2>

<sect2 id="intro-pager">
<title>Pager</title>

<para>
The pager is responsible for showing the email content. On the top of
the pager you have an overview over the most important email headers
like the sender, the recipient, the subject, and much more
information. How much information you actually see depends on your
configuration, which we'll describe below.
</para>

<para>
Below the headers, you see the email body which usually contains the
message. If the email contains any attachments, you will see more
information about them below the email body, or, if the attachments are
text files, you can view them directly in the pager.
</para>

<para>
To give the user a good overview, it is possible to configure Mutt to
show different things in the pager with different colors. Virtually
everything that can be described with a regular expression can be
colored, e.g. URLs, email addresses or smileys.
</para>

</sect2>

<sect2 id="intro-browser">
<title>File Browser</title>

<para>
The file browser is the interface to the local or remote file
system. When selecting a mailbox to open, the browser allows custom
sorting of items, limiting the items shown by a regular expression and a
freely adjustable format of what to display in which way. It also allows
for easy navigation through the file system when selecting file(s) to
attach to a message, select multiple files to attach and many more.
</para>

<para>
Some mail systems can nest mail folders inside other mail folders.
The normal open entry commands in mutt will open the mail folder and
you can't see the sub-folders.  If you instead use the
<literal>&lt;descend-directory&gt;</literal> function it will go into
the directory and not open it as a mail directory.
</para>

</sect2>

<sect2 id="intro-sidebar">
  <title>Sidebar</title>
  <para>
    The Sidebar shows a list of all your mailboxes.  The list can be
    turned on and off, it can be themed and the list style can be
    configured.
  </para>
</sect2>

<sect2 id="intro-help">
<title>Help</title>

<para>
The help screen is meant to offer a quick help to the user. It lists the
current configuration of key bindings and their associated commands
including a short description, and currently unbound functions that
still need to be associated with a key binding (or alternatively, they
can be called via the Mutt command prompt).
</para>

</sect2>

<sect2 id="intro-compose">
<title>Compose Menu</title>

<para>
The compose menu features a split screen containing the information
which really matter before actually sending a message by mail: who gets
the message as what (recipients and who gets what kind of
copy). Additionally, users may set security options like deciding
whether to sign, encrypt or sign and encrypt a message with/for what
keys. Also, it's used to attach messages, to re-edit any attachment
including the message itself.
</para>

</sect2>

<sect2 id="intro-alias">
<title>Alias Menu</title>

<para>
The alias menu is used to help users finding the recipients of
messages. For users who need to contact many people, there's no need to
remember addresses or names completely because it allows for searching,
too. The alias mechanism and thus the alias menu also features grouping
several addresses by a shorter nickname, the actual alias, so that users
don't have to select each single recipient manually.
</para>

</sect2>

<sect2 id="intro-attach">
<title>Attachment Menu</title>

<para>
As will be later discussed in detail, Mutt features a good and stable
MIME implementation, that is, it supports sending and receiving messages
of arbitrary MIME types. The attachment menu displays a message's
structure in detail: what content parts are attached to which parent
part (which gives a true tree structure), which type is of what type and
what size.  Single parts may saved, deleted or modified to offer great
and easy access to message's internals.
</para>

</sect2>

</sect1>

<sect1 id="menus">
<title>Moving Around in Menus</title>

<para>
The most important navigation keys common to line- or entry-based menus
are shown in <xref linkend="tab-keys-nav-line"/> and in <xref
linkend="tab-keys-nav-page"/> for page-based menus.
</para>

<table id="tab-keys-nav-line">
<title>Most common navigation keys in entry-based menus</title>
<tgroup cols="3">
<thead>
<row><entry>Key</entry><entry>Function</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>j or &lt;Down&gt;</entry><entry><literal>&lt;next-entry&gt;</literal></entry><entry>move to the next entry</entry></row>
<row><entry>k or &lt;Up&gt;</entry><entry><literal>&lt;previous-entry&gt;</literal></entry><entry>move to the previous entry</entry></row>
<row><entry>z or &lt;PageDn&gt;</entry><entry><literal>&lt;page-down&gt;</literal></entry><entry>go to the next page</entry></row>
<row><entry>Z or &lt;PageUp&gt;</entry><entry><literal>&lt;page-up&gt;</literal></entry><entry>go to the previous page</entry></row>
<row><entry>= or &lt;Home&gt;</entry><entry><literal>&lt;first-entry&gt;</literal></entry><entry>jump to the first entry</entry></row>
<row><entry>* or &lt;End&gt;</entry><entry><literal>&lt;last-entry&gt;</literal></entry><entry>jump to the last entry</entry></row>
<row><entry>q</entry><entry><literal>&lt;quit&gt;</literal></entry><entry>exit the current menu</entry></row>
<row><entry>?</entry><entry><literal>&lt;help&gt;</literal></entry><entry>list all keybindings for the current menu</entry></row>
</tbody>
</tgroup>
</table>

<table id="tab-keys-nav-page">
<title>Most common navigation keys in page-based menus</title>
<tgroup cols="3">
<thead>
<row><entry>Key</entry><entry>Function</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>J or &lt;Return&gt;</entry><entry><literal>&lt;next-line&gt;</literal></entry><entry>scroll down one line</entry></row>
<row><entry>&lt;Backspace&gt;</entry><entry><literal>&lt;previous-line&gt;</literal></entry><entry>scroll up one line</entry></row>
<row><entry>K, &lt;Space&gt; or &lt;PageDn&gt;</entry><entry><literal>&lt;next-page&gt;</literal></entry><entry>move to the next page</entry></row>
<row><entry>- or &lt;PageUp&gt;</entry><entry><literal>&lt;previous-page&gt;</literal></entry><entry>move the previous page</entry></row>
<row><entry>&lt;Home&gt;</entry><entry><literal>&lt;top&gt;</literal></entry><entry>move to the top</entry></row>
<row><entry>&lt;End&gt;</entry><entry><literal>&lt;bottom&gt;</literal></entry><entry>move to the bottom</entry></row>
</tbody>
</tgroup>
</table>

</sect1>

<sect1 id="editing">
<title>Editing Input Fields</title>

<sect2 id="editing-intro">
<title>Introduction</title>

<para>
Mutt has a built-in line editor for inputting text, e.g. email addresses
or filenames. The keys used to manipulate text input are very similar to
those of Emacs. See <xref linkend="tab-keys-editor"/> for a full
reference of available functions, their default key bindings, and short
descriptions.
</para>

<table id="tab-keys-editor">
<title>Most common line editor keys</title>
<tgroup cols="3">
<thead>
<row><entry>Key</entry><entry>Function</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>^A or &lt;Home&gt;</entry><entry><literal>&lt;bol&gt;</literal></entry><entry>move to the start of the line</entry></row>
<row><entry>^B or &lt;Left&gt;</entry><entry><literal>&lt;backward-char&gt;</literal></entry><entry>move back one char</entry></row>
<row><entry>Esc B</entry><entry><literal>&lt;backward-word&gt;</literal></entry><entry>move back one word</entry></row>
<row><entry>^D or &lt;Delete&gt;</entry><entry><literal>&lt;delete-char&gt;</literal></entry><entry>delete the char under the cursor</entry></row>
<row><entry>^E or &lt;End&gt;</entry><entry><literal>&lt;eol&gt;</literal></entry><entry>move to the end of the line</entry></row>
<row><entry>^F or &lt;Right&gt;</entry><entry><literal>&lt;forward-char&gt;</literal></entry><entry>move forward one char</entry></row>
<row><entry>Esc F</entry><entry><literal>&lt;forward-word&gt;</literal></entry><entry>move forward one word</entry></row>
<row><entry>&lt;Tab&gt;</entry><entry><literal>&lt;complete&gt;</literal></entry><entry>complete filename, alias, or label</entry></row>
<row><entry>^T</entry><entry><literal>&lt;complete-query&gt;</literal></entry><entry>complete address with query</entry></row>
<row><entry>^K</entry><entry><literal>&lt;kill-eol&gt;</literal></entry><entry>delete to the end of the line</entry></row>
<row><entry>Esc d</entry><entry><literal>&lt;kill-eow&gt;</literal></entry><entry>delete to the end of the word</entry></row>
<row><entry>^W</entry><entry><literal>&lt;kill-word&gt;</literal></entry><entry>kill the word in front of the cursor</entry></row>
<row><entry>^U</entry><entry><literal>&lt;kill-line&gt;</literal></entry><entry>delete entire line</entry></row>
<row><entry>^V</entry><entry><literal>&lt;quote-char&gt;</literal></entry><entry>quote the next typed key</entry></row>
<row><entry>&lt;Up&gt;</entry><entry><literal>&lt;history-up&gt;</literal></entry><entry>recall previous string from history</entry></row>
<row><entry>&lt;Down&gt;</entry><entry><literal>&lt;history-down&gt;</literal></entry><entry>recall next string from history</entry></row>
<row><entry>^R</entry><entry><literal>&lt;history-search&gt;</literal></entry><entry>use current input to search history</entry></row>
<row><entry>&lt;BackSpace&gt;</entry><entry><literal>&lt;backspace&gt;</literal></entry><entry>kill the char in front of the cursor</entry></row>
<row><entry>Esc u</entry><entry><literal>&lt;upcase-word&gt;</literal></entry><entry>convert word to upper case</entry></row>
<row><entry>Esc l</entry><entry><literal>&lt;downcase-word&gt;</literal></entry><entry>convert word to lower case</entry></row>
<row><entry>Esc c</entry><entry><literal>&lt;capitalize-word&gt;</literal></entry><entry>capitalize the word</entry></row>
<row><entry>^G</entry><entry>n/a</entry><entry>abort</entry></row>
<row><entry>&lt;Return&gt;</entry><entry>n/a</entry><entry>finish editing</entry></row>
</tbody>
</tgroup>
</table>

<para>
<literal>^G</literal> is the generic <quote>abort</quote> key
in Mutt.  In addition to the line editor, it can also be used
to abort prompts.  Generally, typing <literal>^G</literal> at a
confirmation prompt or line editor should abort the entire action.
</para>

<para>
You can remap the <emphasis>editor</emphasis> functions using the <link
linkend="bind"><command>bind</command></link> command.  For example, to
make the &lt;Delete&gt; key delete the character in front of the cursor
rather than under, you could use:
</para>

<screen>
bind editor &lt;delete&gt; backspace
</screen>

</sect2>

<sect2 id="editing-history">
<title>History</title>

<para>
Mutt maintains a history for the built-in editor.  The number of items
is controlled by the <link linkend="history">$history</link> variable
and can be made persistent using an external file specified using <link
linkend="history-file">$history_file</link> and <link
linkend="save-history">$save_history</link>.  You may cycle through them
at an editor prompt by using the <literal>&lt;history-up&gt;</literal>
and/or <literal>&lt;history-down&gt;</literal> commands.  Mutt will
remember the currently entered text as you cycle through history, and
will wrap around to the initial entry line.
</para>

<para>
Mutt maintains several distinct history lists, one for each of the
following categories:
</para>

<itemizedlist>
<listitem><para><literal>.muttrc</literal> commands</para></listitem>
<listitem><para>addresses and aliases</para></listitem>
<listitem><para>shell commands</para></listitem>
<listitem><para>filenames</para></listitem>
<listitem><para>mailboxes</para></listitem>
<listitem><para>patterns</para></listitem>
<listitem><para>everything else</para></listitem>
</itemizedlist>

<para>
Mutt automatically filters out consecutively repeated items from the
history.  If <link linkend="history-remove-dups">$history_remove_dups</link>
is set, all repeated items are removed from the history.  It also mimics the
behavior of some shells by ignoring items starting with a space. The latter
feature can be useful in macros to not clobber the history's valuable entries
with unwanted entries.
</para>

</sect2>

</sect1>

<sect1 id="reading">
<title>Reading Mail</title>

<para>
Similar to many other mail clients, there are two modes in which mail is
read in Mutt.  The first is a list of messages in the mailbox, which is
called the <quote>index</quote> menu in Mutt.  The second mode is the
display of the message contents.  This is called the
<quote>pager.</quote>
</para>

<para>
The next few sections describe the functions provided in each of these
modes.
</para>

<sect2 id="index-menu">
<title>The Message Index</title>

<para>
Common keys used to navigate through and manage messages in the index
are shown in <xref linkend="tab-key-index"/>. How messages are presented
in the index menu can be customized using the <link
linkend="index-format">$index_format</link> variable.
</para>

<table id="tab-key-index">
<title>Most common message index keys</title>
<tgroup cols="2">
<thead>
<row><entry>Key</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>c</entry><entry>change to a different mailbox</entry></row>
<row><entry>Esc c</entry><entry>change to a folder in read-only mode</entry></row>
<row><entry>C</entry><entry>copy the current message to another mailbox</entry></row>
<row><entry>Esc C</entry><entry>decode a message and copy it to a folder</entry></row>
<row><entry>Esc s</entry><entry>decode a message and save it to a folder</entry></row>
<row><entry>D</entry><entry>delete messages matching a pattern</entry></row>
<row><entry>d</entry><entry>delete the current message</entry></row>
<row><entry>F</entry><entry>mark as important</entry></row>
<row><entry>l</entry><entry>show messages matching a pattern</entry></row>
<row><entry>N</entry><entry>mark message as new</entry></row>
<row><entry>o</entry><entry>change the current sort method</entry></row>
<row><entry>O</entry><entry>reverse sort the mailbox</entry></row>
<row><entry>q</entry><entry>save changes and exit</entry></row>
<row><entry>s</entry><entry>save-message</entry></row>
<row><entry>T</entry><entry>tag messages matching a pattern</entry></row>
<row><entry>t</entry><entry>toggle the tag on a message</entry></row>
<row><entry>Esc t</entry><entry>toggle tag on entire message thread</entry></row>
<row><entry>U</entry><entry>undelete messages matching a pattern</entry></row>
<row><entry>u</entry><entry>undelete-message</entry></row>
<row><entry>v</entry><entry>view-attachments</entry></row>
<row><entry>x</entry><entry>abort changes and exit</entry></row>
<row><entry>&lt;Return&gt;</entry><entry>display-message</entry></row>
<row><entry>&lt;Tab&gt;</entry><entry>jump to the next new or unread message</entry></row>
<row><entry>@</entry><entry>show the author's full e-mail address</entry></row>
<row><entry>$</entry><entry>save changes to mailbox</entry></row>
<row><entry>/</entry><entry>search</entry></row>
<row><entry>Esc /</entry><entry>search-reverse</entry></row>
<row><entry>^L</entry><entry>clear and redraw the screen</entry></row>
<row><entry>^T</entry><entry>untag messages matching a pattern</entry></row>
</tbody>
</tgroup>
</table>

<para>
In addition to who sent the message and the subject, a short summary of
the disposition of each message is printed beside the message number.
Zero or more of the <quote>flags</quote> in <xref
linkend="tab-msg-status-flags"/> may appear, some of which can be turned
on or off using these functions: <literal>&lt;set-flag&gt;</literal> and
<literal>&lt;clear-flag&gt;</literal> bound by default to
<quote>w</quote> and <quote>W</quote> respectively.
</para>

<para>
Furthermore, the flags in <xref linkend="tab-msg-recip-flags"/> reflect
who the message is addressed to. They can be customized with the <link
linkend="to-chars">$to_chars</link> variable.
</para>

<table id="tab-msg-status-flags">
<title>Message status flags</title>
<tgroup cols="2">
<thead>
<row><entry>Flag</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>D</entry><entry>message is deleted (is marked for deletion)</entry></row>
<row><entry>d</entry><entry>message has attachments marked for deletion</entry></row>
<row><entry>K</entry><entry>contains a PGP public key</entry></row>
<row><entry>N</entry><entry>message is new</entry></row>
<row><entry>O</entry><entry>message is old</entry></row>
<row><entry>P</entry><entry>message is PGP encrypted</entry></row>
<row><entry>r</entry><entry>message has been replied to</entry></row>
<row><entry>S</entry><entry>message is signed, and the signature is successfully verified</entry></row>
<row><entry>s</entry><entry>message is signed</entry></row>
<row><entry>!</entry><entry>message is flagged</entry></row>
<row><entry>*</entry><entry>message is tagged</entry></row>
<row><entry>n</entry><entry>thread contains new messages (only if collapsed)</entry></row>
<row><entry>o</entry><entry>thread contains old messages (only if collapsed)</entry></row>
</tbody>
</tgroup>
</table>

<table id="tab-msg-recip-flags">
<title>Message recipient flags</title>
<tgroup cols="2">
<thead>
<row><entry>Flag</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>+</entry><entry>message is to you and you only</entry></row>
<row><entry>T</entry><entry>message is to you, but also to or CC'ed to others</entry></row>
<row><entry>C</entry><entry>message is CC'ed to you</entry></row>
<row><entry>F</entry><entry>message is from you</entry></row>
<row><entry>L</entry><entry>message is sent to a subscribed mailing list</entry></row>
</tbody>
</tgroup>
</table>

</sect2>

<sect2 id="pager-menu">
<title>The Pager</title>

<para>
By default, Mutt uses its built-in pager to display the contents of
messages (an external pager such as <literal>less(1)</literal> can be
configured, see <link linkend="pager">$pager</link> variable).  The
pager is very similar to the Unix program <literal>less(1)</literal>
though not nearly as featureful.
</para>

<table id="tab-key-pager">
<title>Most common pager keys</title>
<tgroup cols="2">
<thead>
<row><entry>Key</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>&lt;Return&gt;</entry><entry>go down one line</entry></row>
<row><entry>&lt;Space&gt;</entry><entry>display the next page (or next message if at the end of a message)</entry></row>
<row><entry>-</entry><entry>go back to the previous page</entry></row>
<row><entry>n</entry><entry>search for next match</entry></row>
<row><entry>S</entry><entry>skip beyond quoted text</entry></row>
<row><entry>T</entry><entry>toggle display of quoted text</entry></row>
<row><entry>?</entry><entry>show keybindings</entry></row>
<row><entry>/</entry><entry>regular expression search</entry></row>
<row><entry>Esc /</entry><entry>backward regular expression search</entry></row>
<row><entry>\</entry><entry>toggle highlighting of search matches</entry></row>
<row><entry>^</entry><entry>jump to the top of the message</entry></row>
</tbody>
</tgroup>
</table>

<para>
In addition to key bindings in <xref linkend="tab-key-pager"/>, many of
the functions from the index menu are also available in the pager, such
as <literal>&lt;delete-message&gt;</literal> or
<literal>&lt;copy-message&gt;</literal> (this is one advantage over
using an external pager to view messages).
</para>

<para>
Also, the internal pager supports a couple other advanced features. For
one, it will accept and translate the <quote>standard</quote> nroff
sequences for bold and underline. These sequences are a series of either
the letter, backspace (<quote>^H</quote>), the letter again for bold or
the letter, backspace, <quote>_</quote> for denoting underline. Mutt
will attempt to display these in bold and underline respectively if your
terminal supports them. If not, you can use the bold and underline <link
linkend="color">color</link> objects to specify a
<command>color</command> or mono attribute for them.
</para>

<para>
Additionally, the internal pager supports the ANSI escape sequences for
character attributes.  Mutt translates them into the correct color and
character settings.  The sequences Mutt supports are:
</para>

<screen>
\e[<emphasis>Ps</emphasis>;<emphasis>Ps</emphasis>;..<emphasis>Ps</emphasis>;m
</screen>

<para>
where <emphasis>Ps</emphasis> can be one of the codes shown in <xref
linkend="tab-ansi-esc"/>.
</para>

<table id="tab-ansi-esc">
<title>ANSI escape sequences</title>
<tgroup cols="2">
<thead>
<row><entry>Escape code</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>0</entry><entry>All attributes off</entry></row>
<row><entry>1</entry><entry>Bold on</entry></row>
<row><entry>4</entry><entry>Underline on</entry></row>
<row><entry>5</entry><entry>Blink on</entry></row>
<row><entry>7</entry><entry>Reverse video on</entry></row>
<row><entry>3<emphasis>&lt;color&gt;</emphasis></entry><entry>Foreground color is <emphasis>&lt;color&gt;</emphasis> (see <xref linkend="tab-color"/>)</entry></row>
<row><entry>4<emphasis>&lt;color&gt;</emphasis></entry><entry>Background color is <emphasis>&lt;color&gt;</emphasis> (see <xref linkend="tab-color"/>)</entry></row>
</tbody>
</tgroup>
</table>

<table id="tab-color">
<title>Color sequences</title>
<tgroup cols="2">
<thead>
<row><entry>Color code</entry><entry>Color</entry></row>
</thead>
<tbody>
<row><entry>0</entry><entry>Black</entry></row>
<row><entry>1</entry><entry>Red</entry></row>
<row><entry>2</entry><entry>Green</entry></row>
<row><entry>3</entry><entry>Yellow</entry></row>
<row><entry>4</entry><entry>Blue</entry></row>
<row><entry>5</entry><entry>Magenta</entry></row>
<row><entry>6</entry><entry>Cyan</entry></row>
<row><entry>7</entry><entry>White</entry></row>
</tbody>
</tgroup>
</table>

<para>
Mutt uses these attributes for handling <literal>text/enriched</literal>
messages, and they can also be used by an external <link
linkend="auto-view">autoview</link> script for highlighting purposes.
</para>

<note>
<para>
If you change the colors for your display, for example by changing the
color associated with color2 for your xterm, then that color will be
used instead of green.
</para>
</note>

<note>
<para>
Note that the search commands in the pager take regular expressions,
which are not quite the same as the more complex <link
linkend="patterns">patterns</link> used by the search command in the
index. This is because patterns are used to select messages by criteria
whereas the pager already displays a selected message.
</para>
</note>

</sect2>

<sect2 id="threads">
<title>Threaded Mode</title>

<para>
So-called <quote>threads</quote> provide a hierarchy of messages where
replies are linked to their parent message(s). This organizational form
is extremely useful in mailing lists where different parts of the
discussion diverge. Mutt displays threads as a tree structure.
</para>

<para>
In Mutt, when a mailbox is <link linkend="sort">sorted</link>
by <emphasis>threads</emphasis>, there are a few additional functions
available in the <emphasis>index</emphasis>
and <emphasis>pager</emphasis> modes as shown in
<xref linkend="tab-key-threads"/>.
</para>

<table id="tab-key-threads">
<title>Most common thread mode keys</title>
<tgroup cols="3">
<thead>
<row><entry>Key</entry><entry>Function</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>^D</entry><entry><literal>&lt;delete-thread&gt;</literal></entry><entry>delete all messages in the current thread</entry></row>
<row><entry>^U</entry><entry><literal>&lt;undelete-thread&gt;</literal></entry><entry>undelete all messages in the current thread</entry></row>
<row><entry>^N</entry><entry><literal>&lt;next-thread&gt;</literal></entry><entry>jump to the start of the next thread</entry></row>
<row><entry>^P</entry><entry><literal>&lt;previous-thread&gt;</literal></entry><entry>jump to the start of the previous thread</entry></row>
<row><entry>^R</entry><entry><literal>&lt;read-thread&gt;</literal></entry><entry>mark the current thread as read</entry></row>
<row><entry>Esc d</entry><entry><literal>&lt;delete-subthread&gt;</literal></entry><entry>delete all messages in the current subthread</entry></row>
<row><entry>Esc u</entry><entry><literal>&lt;undelete-subthread&gt;</literal></entry><entry>undelete all messages in the current subthread</entry></row>
<row><entry>Esc n</entry><entry><literal>&lt;next-subthread&gt;</literal></entry><entry>jump to the start of the next subthread</entry></row>
<row><entry>Esc p</entry><entry><literal>&lt;previous-subthread&gt;</literal></entry><entry>jump to the start of the previous subthread</entry></row>
<row><entry>Esc r</entry><entry><literal>&lt;read-subthread&gt;</literal></entry><entry>mark the current subthread as read</entry></row>
<row><entry>Esc t</entry><entry><literal>&lt;tag-thread&gt;</literal></entry><entry>toggle the tag on the current thread</entry></row>
<row><entry>Esc v</entry><entry><literal>&lt;collapse-thread&gt;</literal></entry><entry>toggle collapse for the current thread</entry></row>
<row><entry>Esc V</entry><entry><literal>&lt;collapse-all&gt;</literal></entry><entry>toggle collapse for all threads</entry></row>
<row><entry>P</entry><entry><literal>&lt;parent-message&gt;</literal></entry><entry>jump to parent message in thread</entry></row>
</tbody>
</tgroup>
</table>

<para>
In the <emphasis>index</emphasis>, the subject of threaded children
messages will be prepended with thread tree characters.  By default,
the subject itself will not be duplicated unless <link
linkend="hide-thread-subject">$hide_thread_subject</link> is unset.
Special characters will be added to the thread tree as detailed in
<xref linkend="tab-thread-chars"/>.
</para>

<table id="tab-thread-chars">
  <title>Special Thread Characters</title>
  <tgroup cols="3">
    <thead>
      <row>
        <entry>Character</entry>
        <entry>Description</entry>
        <entry>Notes</entry>
      </row>
    </thead>
    <tbody>
      <row>
        <entry>&amp;</entry>
        <entry>hidden message</entry>
        <entry>see <link linkend="hide-limited">$hide_limited</link> and
        <link linkend="hide-top-limited">$hide_top_limited</link></entry>
      </row>
      <row>
        <entry>?</entry>
        <entry>missing message</entry>
        <entry>see <link linkend="hide-missing">$hide_missing</link> and
        <link linkend="hide-top-missing">$hide_top_missing</link></entry>
      </row>
      <row>
        <entry>*</entry>
        <entry>pseudo thread</entry>
        <entry>see <link linkend="strict-threads">$strict_threads</link>;
        not displayed when
        <link linkend="narrow-tree">$narrow_tree</link> is set</entry>
      </row>
      <row>
        <entry>=</entry>
        <entry>duplicate thread</entry>
        <entry>see <link linkend="duplicate-threads">$duplicate_threads</link>;
        not displayed when
        <link linkend="narrow-tree">$narrow_tree</link> is set</entry>
      </row>
    </tbody>
  </tgroup>
</table>

<para>
Collapsing a thread displays only the first message in the thread and
hides the others. This is useful when threads contain so many messages
that you can only see a handful of threads on the screen. See %M in
<link linkend="index-format">$index_format</link>.  For example, you
could use <quote>%?M?(#%03M)&amp;(%4l)?</quote> in <link
linkend="index-format">$index_format</link> to optionally display the
number of hidden messages if the thread is collapsed. The
<literal>%?&lt;char&gt;?&lt;if-part&gt;&amp;&lt;else-part&gt;?</literal>
syntax is explained in detail in <link
linkend="formatstrings-conditionals">format string conditionals</link>.
</para>

<para>
Technically, every reply should contain a list of its parent messages in
the thread tree, but not all do. In these cases, Mutt groups them by
subject which can be controlled using the <link
linkend="strict-threads">$strict_threads</link> variable.
</para>

</sect2>

<sect2 id="reading-misc">
<title>Miscellaneous Functions</title>

<para>
In addition, the <emphasis>index</emphasis> and
<emphasis>pager</emphasis> menus have these interesting functions:
</para>

<variablelist>

<varlistentry>
<term>
<literal>&lt;check-stats&gt;</literal><anchor id="check-stats"/>
</term>
<listitem>
<para>
Calculate statistics for all monitored mailboxes declared using the
<command>mailboxes</command> command.
It will calculate statistics despite
<link linkend="mail-check-stats">$mail_check_stats</link> being unset.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>
<literal>&lt;create-alias&gt;</literal><anchor id="create-alias"/>
(default: a)
</term>
<listitem>
<para>
Creates a new alias based upon the current message (or prompts for a new
one).  Once editing is complete, an <link
linkend="alias"><command>alias</command></link> command is added to the
file specified by the <link linkend="alias-file">$alias_file</link>
variable for future use
</para>

<note>
<para>
Mutt does not read the <link linkend="alias-file">$alias_file</link>
upon startup so you must explicitly <link
linkend="source"><command>source</command></link> the file.
</para>
</note>
</listitem>
</varlistentry>

<varlistentry>
<term>
<literal>&lt;check-traditional-pgp&gt;</literal><anchor
id="check-traditional-pgp"/> (default: Esc P)
</term>
<listitem>
<para>
This function will search the current message for content signed or
encrypted with PGP the <quote>traditional</quote> way, that is, without
proper MIME tagging.  Technically, this function will temporarily change
the MIME content types of the body parts containing PGP data; this is
similar to the <link
linkend="edit-type"><literal>&lt;edit-type&gt;</literal></link>
function's effect.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>
<literal>&lt;edit&gt;</literal><anchor id="edit"/> (default: e)
</term>
<listitem>
<para>
This command (available in the index and pager) allows you to edit the
raw current message as it's present in the mail folder.  After you have
finished editing, the changed message will be appended to the current
folder, and the original message will be marked for deletion; if the
message is unchanged it won't be replaced.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>
<literal>&lt;edit-type&gt;</literal><anchor id="edit-type"/> (default:
^E on the attachment menu, and in the pager and index menus; ^T on the
compose menu)
</term>
<listitem>
<para>
This command is used to temporarily edit an attachment's content type to
fix, for instance, bogus character set parameters.  When invoked from
the index or from the pager, you'll have the opportunity to edit the
top-level attachment's content type.  On the <link
linkend="attach-menu">attachment menu</link>, you can change any
attachment's content type. These changes are not persistent, and get
lost upon changing folders.
</para>

<para>
Note that this command is also available on the <link
linkend="compose-menu">compose menu</link>.  There, it's used to
fine-tune the properties of attachments you are going to send.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>
<literal>&lt;enter-command&gt;</literal><anchor id="enter-command"/>
(default: <quote>:</quote>)
</term>
<listitem>
<para>
This command is used to execute any command you would normally put in a
configuration file.  A common use is to check the settings of variables,
or in conjunction with <link linkend="macro">macros</link> to change
settings on the fly.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>
<literal>&lt;extract-keys&gt;</literal><anchor id="extract-keys"/>
(default: ^K)
</term>
<listitem>
<para>
This command extracts PGP public keys from the current or tagged
message(s) and adds them to your PGP public key ring.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>
<literal>&lt;forget-passphrase&gt;</literal><anchor
id="forget-passphrase"/> (default: ^F)
</term>
<listitem>
<para>
This command wipes the passphrase(s) from memory. It is useful, if you
misspelled the passphrase.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>
<literal>&lt;list-reply&gt;</literal><anchor id="list-reply"/> (default:
L)
</term>
<listitem>
<para>
Reply to the current or tagged message(s) by extracting any addresses
which match the regular expressions given by the <link
linkend="lists"><command>lists</command> or
<command>subscribe</command></link> commands, but also honor any
<literal>Mail-Followup-To</literal> header(s) if the <link
linkend="honor-followup-to">$honor_followup_to</link> configuration
variable is set.  In addition, the <literal>List-Post</literal> header field is
examined for <literal>mailto:</literal> URLs specifying a mailing list address.
Using this when replying to messages posted to mailing lists helps avoid
duplicate copies being sent to the author of the message you are replying to.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>
<literal>&lt;pipe-message&gt;</literal><anchor id="pipe-message"/>
(default: |)
</term>
<listitem>
<para>
Asks for an external Unix command and pipes the current or tagged
message(s) to it.  The variables <link
linkend="pipe-decode">$pipe_decode</link>, <link
linkend="pipe-decode-weed">$pipe_decode_weed</link>, <link
linkend="pipe-split">$pipe_split</link>, <link
linkend="pipe-sep">$pipe_sep</link> and <link
linkend="wait-key">$wait_key</link> control the exact behavior of this
function.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>
<literal>&lt;resend-message&gt;</literal><anchor id="resend-message"/>
(default: Esc e)
</term>
<listitem>
<para>
Mutt takes the current message as a template for a new message.  This
function is best described as "recall from arbitrary folders".  It can
conveniently be used to forward MIME messages while preserving the
original mail structure. Note that the amount of headers included here
depends on the value of the <link linkend="weed">$weed</link> variable.
</para>

<para>
This function is also available from the attachment menu. You can use
this to easily resend a message which was included with a bounce message
as a <literal>message/rfc822</literal> body part.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>
<literal>&lt;shell-escape&gt;</literal><anchor id="shell-escape"/>
(default: !)
</term>
<listitem>
<para>
Asks for an external Unix command and executes it.  The <link
linkend="wait-key">$wait_key</link> can be used to control whether Mutt
will wait for a key to be pressed when the command returns (presumably
to let the user read the output of the command), based on the return
status of the named command. If no command is given, an interactive
shell is executed.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>
<literal>&lt;toggle-quoted&gt;</literal><anchor id="toggle-quoted"/>
(default: T)
</term>
<listitem>
<para>
The pager uses the <link linkend="quote-regexp">$quote_regexp</link>
variable to detect quoted text when displaying the body of the message.
This function toggles the display of the quoted material in the message.
It is particularly useful when being interested in just the response and
there is a large amount of quoted text in the way.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>
<literal>&lt;skip-quoted&gt;</literal><anchor id="skip-quoted"/>
(default: S)
</term>
<listitem>
<para>
This function will go to the next line of non-quoted text which comes
after a line of quoted text in the internal pager.
</para>
</listitem>
</varlistentry>

</variablelist>

</sect2>

</sect1>

<sect1 id="sending">
<title>Sending Mail</title>

<sect2 id="sending-intro">
<title>Introduction</title>

<para>
The bindings shown in <xref linkend="tab-key-send"/> are available in
the <emphasis>index</emphasis> and <emphasis>pager</emphasis> to start a
new message.
</para>

<table id="tab-key-send">
<title>Most common mail sending keys</title>
<tgroup cols="3">
<thead>
<row><entry>Key</entry><entry>Function</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>m</entry><entry><literal>&lt;mail&gt;</literal></entry><entry>compose a new message</entry></row>
<row><entry>r</entry><entry><literal>&lt;reply&gt;</literal></entry><entry>reply to sender</entry></row>
<row><entry>g</entry><entry><literal>&lt;group-reply&gt;</literal></entry><entry>reply to all recipients</entry></row>
<row><entry></entry><entry><literal>&lt;group-chat-reply&gt;</literal></entry><entry>reply to all recipients preserving To/Cc</entry></row>
<row><entry>L</entry><entry><literal>&lt;list-reply&gt;</literal></entry><entry>reply to mailing list address</entry></row>
<row><entry>f</entry><entry><literal>&lt;forward&gt;</literal></entry><entry>forward message</entry></row>
<row><entry>b</entry><entry><literal>&lt;bounce&gt;</literal></entry><entry>bounce (remail) message</entry></row>
<row><entry>Esc k</entry><entry><literal>&lt;mail-key&gt;</literal></entry><entry>mail a PGP public key to someone</entry></row>
</tbody>
</tgroup>
</table>

<para>
<emphasis>Bouncing</emphasis> a message sends the message as-is to the
recipient you specify.  <emphasis>Forwarding</emphasis> a message allows
you to add comments or modify the message you are forwarding.  These
items are discussed in greater detail in the next section <quote><link
linkend="forwarding-mail">Forwarding and Bouncing Mail</link>.</quote>
</para>

<para>
Mutt will then enter the <emphasis>compose</emphasis> menu and prompt
you for the recipients to place on the <quote>To:</quote> header field
when you hit <literal>m</literal> to start a new message. Next, it will
ask you for the <quote>Subject:</quote> field for the message, providing
a default if you are replying to or forwarding a message. You again have
the chance to adjust recipients, subject, and security settings right
before actually sending the message. See also <link
linkend="askcc">$askcc</link>, <link linkend="askbcc">$askbcc</link>,
<link linkend="autoedit">$autoedit</link>, <link
linkend="bounce">$bounce</link>, <link
linkend="fast-reply">$fast_reply</link>, and <link
linkend="include">$include</link> for changing how and if Mutt asks
these questions.
</para>

<para>
When replying, Mutt fills these fields with proper values depending on
the reply type.  The types of replying supported are:
</para>

<variablelist>
<varlistentry>
<term>Simple reply</term>
<listitem>
<para>
Reply to the author directly.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Group reply</term>
<listitem>
<para>
Reply to the author; cc all other recipients; consults
<link linkend="alternates"><command>alternates</command></link>
and excludes you.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Group Chat reply</term>
<listitem>
<para>
Reply to the author and other recipients in the To list;
cc other recipients in the Cc list; consults
<link linkend="alternates"><command>alternates</command></link>
and excludes you.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>List reply</term>
<listitem>
<para>
Reply to all mailing list addresses found, either specified via
configuration or auto-detected.  See <xref linkend="lists"/> for
details.
</para>
</listitem>
</varlistentry>
</variablelist>

<para>
After getting recipients for new messages, forwards or replies, Mutt
will then automatically start your <link linkend="editor">$editor</link>
on the message body. If the <link
linkend="edit-headers">$edit_headers</link> variable is set, the headers
will be at the top of the message in your editor; the message body
should start on a new line after the existing blank line at the end of
headers.  Any messages you are replying to will be added in sort order
to the message, with appropriate
<link linkend="attribution">$attribution</link>, <link
linkend="indent-string">$indent_string</link> and <link
linkend="post-indent-string">$post_indent_string</link>.  When
forwarding a message, if the <link
linkend="mime-forward">$mime_forward</link> variable is unset, a copy of
the forwarded message will be included.  If you have specified a <link
linkend="signature">$signature</link>, it will be appended to the
message.
</para>

<para>
Once you have finished editing the body of your mail message, you are
returned to the <emphasis>compose</emphasis> menu providing the
functions shown in <xref linkend="tab-func-compose"/> to modify, send or
postpone the message.
</para>

<table id="tab-func-compose">
<title>Most common compose menu keys</title>
<tgroup cols="3">
<thead>
<row><entry>Key</entry><entry>Function</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>a</entry><entry><literal>&lt;attach-file&gt;</literal></entry><entry>attach a file</entry></row>
<row><entry>A</entry><entry><literal>&lt;attach-message&gt;</literal></entry><entry>attach message(s) to the message</entry></row>
<row><entry>Esc k</entry><entry><literal>&lt;attach-key&gt;</literal></entry><entry>attach a PGP public key</entry></row>
<row><entry>d</entry><entry><literal>&lt;edit-description&gt;</literal></entry><entry>edit description on attachment</entry></row>
<row><entry>D</entry><entry><literal>&lt;detach-file&gt;</literal></entry><entry>detach a file</entry></row>
<row><entry>t</entry><entry><literal>&lt;edit-to&gt;</literal></entry><entry>edit the To field</entry></row>
<row><entry>Esc f</entry><entry><literal>&lt;edit-from&gt;</literal></entry><entry>edit the From field</entry></row>
<row><entry>r</entry><entry><literal>&lt;edit-reply-to&gt;</literal></entry><entry>edit the Reply-To field</entry></row>
<row><entry>c</entry><entry><literal>&lt;edit-cc&gt;</literal></entry><entry>edit the Cc field</entry></row>
<row><entry>b</entry><entry><literal>&lt;edit-bcc&gt;</literal></entry><entry>edit the Bcc field</entry></row>
<row><entry>y</entry><entry><literal>&lt;send-message&gt;</literal></entry><entry>send the message</entry></row>
<row><entry>s</entry><entry><literal>&lt;edit-subject&gt;</literal></entry><entry>edit the Subject</entry></row>
<row><entry>S</entry><entry><literal>&lt;smime-menu&gt;</literal></entry><entry>select S/MIME options</entry></row>
<row><entry>f</entry><entry><literal>&lt;edit-fcc&gt;</literal></entry><entry>specify an <quote>Fcc</quote> mailbox</entry></row>
<row><entry>p</entry><entry><literal>&lt;pgp-menu&gt;</literal></entry><entry>select PGP options</entry></row>
<row><entry>P</entry><entry><literal>&lt;postpone-message&gt;</literal></entry><entry>postpone this message until later</entry></row>
<row><entry>q</entry><entry><literal>&lt;quit&gt;</literal></entry><entry>quit (abort) sending the message</entry></row>
<row><entry>w</entry><entry><literal>&lt;write-fcc&gt;</literal></entry><entry>write the message to a folder</entry></row>
<row><entry>i</entry><entry><literal>&lt;ispell&gt;</literal></entry><entry>check spelling (if available on your system)</entry></row>
<row><entry>^F</entry><entry><literal>&lt;forget-passphrase&gt;</literal></entry><entry>wipe passphrase(s) from memory</entry></row>
</tbody>
</tgroup>
</table>

<para>
The compose menu is also used to edit the attachments for a message
which can be either files or other messages. The
<literal>&lt;attach-message&gt;</literal> function to will prompt you
for a folder to attach messages from. You can now tag messages in that
folder and they will be attached to the message you are sending.
</para>

<note>
<para>
Note that certain operations like composing a new mail, replying,
forwarding, etc. are not permitted when you are in that folder. The %r
in <link linkend="status-format">$status_format</link> will change to a
<quote>A</quote> to indicate that you are in attach-message mode.
</para>
</note>

<para>
After exiting the compose menu via <literal>&lt;send-message&gt;</literal>,
the message will be sent.  If configured and enabled, this can happen via
<link linkend="sending-mixmaster">mixmaster</link> or
<link linkend="smtp">$smtp_url</link>.  Otherwise
<link linkend="sendmail">$sendmail</link> will be invoked.  Prior to
version 1.13, Mutt enabled <link linkend="write-bcc">$write_bcc</link> by
default, assuming the MTA would automatically remove a
<literal>Bcc:</literal> header as part of delivery.  Starting with 1.13, the
option is unset by default, but no longer affects the fcc copy of the message.
</para>

</sect2>

<sect2 id="edit-header">
<title>Editing the Message Header</title>

<para>
When editing the header because of <link
linkend="edit-headers">$edit_headers</link> being set, there are a
several pseudo headers available which will not be included in sent
messages but trigger special Mutt behavior.
</para>

<sect3 id="fcc-header">
<title>Fcc: Pseudo Header</title>

<para>
If you specify
</para>

<para>
<literal>Fcc:</literal> <emphasis>filename</emphasis>
</para>

<para>
as a header, Mutt will pick up <emphasis>filename</emphasis> just as if
you had used the <literal>&lt;edit-fcc&gt;</literal> function in the
<emphasis>compose</emphasis> menu.  It can later be changed from the
compose menu.
</para>

</sect3>

<sect3 id="attach-header">
<title>Attach: Pseudo Header</title>

<para>
You can also attach files to your message by specifying
</para>

<para>
<literal>Attach:</literal> <emphasis>filename</emphasis>
[ <emphasis>description</emphasis> ]
</para>

<para>
where <emphasis>filename</emphasis> is the file to attach and
<emphasis>description</emphasis> is an optional string to use as the
description of the attached file. Spaces in filenames have to be escaped
using backslash (<quote>\</quote>).  The file can be removed as well as
more added from the compose menu.
</para>

</sect3>

<sect3 id="pgp-header">
<title>Pgp: Pseudo Header</title>

<para>
If you want to use PGP, you can specify
</para>

<para>
<literal>Pgp:</literal> [ <literal>E</literal> | <literal>S</literal> | <literal>S</literal><emphasis>&lt;id&gt;</emphasis> ]

</para>

<para>
<quote>E</quote> selects encryption, <quote>S</quote> selects signing
and <quote>S&lt;id&gt;</quote> selects signing with the given key,
setting <link linkend="pgp-sign-as">$pgp_sign_as</link> for the
duration of the message composition session. The selection can later
be changed in the compose menu.
</para>

</sect3>

<sect3 id="in-reply-to-header">
<title>In-Reply-To: Header</title>

<para>
When replying to messages, the <emphasis>In-Reply-To:</emphasis> header
contains the Message-Id of the message(s) you reply to. If you remove or
modify its value, Mutt will not generate a
<emphasis>References:</emphasis> field, which allows you to create a new
message thread, for example to create a new message to a mailing list
without having to enter the mailing list's address.
</para>

<para>
If you intend to start a new thread by replying, please make really sure
you remove the <emphasis>In-Reply-To:</emphasis> header in your
editor. Otherwise, though you'll produce a technically valid reply, some
netiquette guardians will be annoyed by this so-called <quote>thread
hijacking</quote>.
</para>

</sect3>

</sect2>

<sect2 id="sending-crypto">
<title>Sending Cryptographically Signed/Encrypted Messages</title>

<para>
If you have told Mutt to PGP or S/MIME encrypt a message, it will guide
you through a key selection process when you try to send the message.
Mutt will not ask you any questions about keys which have a certified
user ID matching one of the message recipients' mail addresses.
However, there may be situations in which there are several keys, weakly
certified user ID fields, or where no matching keys can be found.
</para>

<para>
In these cases, you are dropped into a menu with a list of keys from
which you can select one.  When you quit this menu, or Mutt can't find
any matching keys, you are prompted for a user ID.  You can, as usually,
abort this prompt using <literal>^G</literal>.  When you do so, Mutt
will return to the compose screen.
</para>

<para>
Once you have successfully finished the key selection, the message will
be encrypted using the selected public keys when sent out.
</para>

<para>
To ensure you can view encrypted messages you have sent, you
may wish to set <link linkend="pgp-self-encrypt">$pgp_self_encrypt</link>
and <link linkend="pgp-default-key">$pgp_default_key</link> for PGP, or
<link linkend="smime-self-encrypt">$smime_self_encrypt</link>
and <link linkend="smime-default-key">$smime_default_key</link> for S/MIME.
</para>

<para>
Most fields of the entries in the key selection menu (see also <link
linkend="pgp-entry-format">$pgp_entry_format</link>) have obvious
meanings.  But some explanations on the capabilities, flags, and
validity fields are in order.
</para>

<para>
The flags sequence (<quote>%f</quote>) will expand to one of the flags
in <xref linkend="tab-pgp-menuflags"/>.
</para>

<table id="tab-pgp-menuflags">
<title>PGP key menu flags</title>
<tgroup cols="2">
<thead>
<row><entry>Flag</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>R</entry><entry>The key has been revoked and can't be used.</entry></row>
<row><entry>X</entry><entry>The key is expired and can't be used.</entry></row>
<row><entry>d</entry><entry>You have marked the key as disabled.</entry></row>
<row><entry>c</entry><entry>There are unknown critical self-signature packets.</entry></row>
</tbody>
</tgroup>
</table>

<para>
The capabilities field (<quote>%c</quote>) expands to a two-character
sequence representing a key's capabilities.  The first character gives
the key's encryption capabilities: A minus sign (<quote>-</quote>) means
that the key cannot be used for encryption.  A dot (<quote>.</quote>)
means that it's marked as a signature key in one of the user IDs, but
may also be used for encryption.  The letter <quote>e</quote> indicates
that this key can be used for encryption.
</para>

<para>
The second character indicates the key's signing capabilities.  Once
again, a <quote>-</quote> implies <quote>not for signing</quote>,
<quote>.</quote> implies that the key is marked as an encryption key in
one of the user-ids, and <quote>s</quote> denotes a key which can be
used for signing.
</para>

<para>
Finally, the validity field (<quote>%t</quote>) indicates how
well-certified a user-id is.  A question mark (<quote>?</quote>)
indicates undefined validity, a minus character (<quote>-</quote>) marks
an untrusted association, a space character means a partially trusted
association, and a plus character (<quote>+</quote>) indicates complete
validity.
</para>

</sect2>

<sect2 id="ff">
<title>Sending Format=Flowed Messages</title>

<sect3 id="ff-concept">
<title>Concept</title>

<para>
<literal>format=flowed</literal>-style messages (or
<literal>f=f</literal> for short) are <literal>text/plain</literal>
messages that consist of paragraphs which a receiver's mail client may
reformat to its own needs which mostly means to customize line lengths
regardless of what the sender sent. Technically this is achieved by
letting lines of a <quote>flowable</quote> paragraph end in spaces
except for the last line.
</para>

<para>
While for text-mode clients like Mutt it's the best way to assume only a
standard 80x25 character cell terminal, it may be desired to let the
receiver decide completely how to view a message.
</para>

</sect3>

<sect3 id="ff-support">
<title>Mutt Support</title>

<para>
Mutt only supports setting the required <literal>format=flowed</literal>
MIME parameter on outgoing messages if the <link
linkend="text-flowed">$text_flowed</link> variable is set, specifically
it does not add the trailing spaces.
</para>

<para>
After editing, Mutt properly space-stuffs the message.
<emphasis>Space-stuffing</emphasis> is required by RfC3676 defining
<literal>format=flowed</literal> and means to prepend a space to:
</para>

<itemizedlist>
<listitem><para>all lines starting with a space</para></listitem>
<listitem><para>lines starting with the word
<quote><literal>From</literal></quote> followed by
space</para></listitem>
<listitem><para>all lines starting with
<quote><literal>&gt;</literal></quote> which is not intended to be a
quote character</para></listitem>
</itemizedlist>

<note>
<para>
Mutt only supports space-stuffing for the first two types of lines but
not for the third: It is impossible to safely detect whether a leading
<literal>&gt;</literal> character starts a quote or not.
</para>
</note>

<para>
All leading spaces are to be removed by receiving clients to restore the
original message prior to further processing.
</para>

</sect3>

<sect3 id="ff-editor">
<title>Editor Considerations</title>

<para>
As Mutt provides no additional features to compose
<literal>f=f</literal> messages, it's completely up to the user and his
editor to produce proper messages. Please consider your editor's
documentation if you intend to send <literal>f=f</literal> messages.
</para>

<para>
For example, <emphasis>vim</emphasis> provides the <literal>w</literal>
flag for its <literal>formatoptions</literal> setting to assist in
creating <literal>f=f</literal> messages, see <literal>:help
fo-table</literal> for details.
</para>

</sect3>

<sect3 id="ff-pager">
<title>Reformatting</title>

<para>
  Mutt has some support for reformatting when viewing and replying to
  <literal>format=flowed</literal> messages.  In order to take advantage of these,
  <link linkend="reflow-text">$reflow_text</link> must be set.
</para>

<itemizedlist>
  <listitem>
  <para>
    Paragraphs are automatically reflowed and wrapped at a width specified
    by <link linkend="reflow-wrap">$reflow_wrap</link>.
  </para>
  </listitem>
  <listitem>
  <para>
    In its original format, the quoting style of <literal>format=flowed</literal>
    messages can be difficult to read, and doesn't intermix well with
    non-flowed replies.
    Setting <link linkend="reflow-space-quotes">$reflow_space_quotes</link>
    adds spaces after each level of quoting when in the pager and
    replying in a non-flowed format
    (i.e. with <link linkend="text-flowed">$text_flowed</link> unset).
  </para>
  </listitem>
  <listitem>
  <para>
    If <link linkend="reflow-space-quotes">$reflow_space_quotes</link>
    is unset, mutt will still add one trailing space after all the
    quotes in the pager (but not when replying).
  </para>
  </listitem>
</itemizedlist>

</sect3>

</sect2>

<sect2 id="bgedit">
<title>Background Editing</title>

<para>
  If <link linkend="editor">$editor</link> is set to a graphical
  editor, or a script such as <ulink
  url="https://gitlab.com/muttmua/mutt/tree/master/contrib/bgedit-screen-tmux.sh"
  >contrib/bgedit-screen-tmux.sh</ulink> if running inside GNU Screen or
  tmux, you can run the editor in the background by setting <link
  linkend="background-edit">$background_edit</link>.
</para>
<para>
  If set, Mutt will display a landing page while the editor runs.
  When the editor exits, message composition will resume
  automatically.  Alternatively, you can
  <literal>&lt;exit&gt;</literal> from the landing page, which will
  return you to the message index.  This allows viewing other
  messages, changing mailboxes, even starting a new message
  composition session - all while the first editor session is still
  running.
</para>
<para>
  Backgrounded message composition sessions can be viewed via
  <literal>&lt;background-compose-menu&gt;</literal> in the index and
  pager, by default bound to <quote><literal>B</literal></quote>.  If
  there is only a single backgrounded session, which has already
  exited, that session will automatically resume.  Otherwise the list
  will be displayed, and a particular session can be selected.  <link
  linkend="background-format">$background_format</link> controls the
  format string used for the menu.
</para>
<para>
  In case the open mailbox is changed while a reply is backgrounded,
  Mutt keeps track of the original mailbox.  After sending, Mutt will
  attempt to reopen the original mailbox, if needed, and set reply
  flags appropriately.  This won't affect your currently open mailbox,
  but may make setting flags a bit slower due to the need to reopen
  the original mailbox behind the scenes.
</para>
<para>
  One complication with backgrounded compose sessions is the config
  changes caused by <link linkend="hooks">send, reply, and folder
  hooks</link>.  These can get triggered by a new message composition
  session, or by changing folders during a backgrounded session.  To
  help lessen these problems, Mutt takes a snapshot of certain
  configuration variables and stores them with each editing session
  when it is backgrounded.  When the session is resumed, those stored
  settings will temporarily be restored, and removed again when the
  session finishes (or is backgrounded again).
</para>
<para>
  Mutt will save all <literal>boolean</literal> and
  <literal>quadoption</literal> configuration variables,
  the current folder (which will be used for <literal>^</literal>
  mailbox shortcut expansion), along with:
  <link linkend="folder">$folder</link>,
  <link linkend="record">$record</link>,
  <link linkend="postponed">$postponed</link>,
  <link linkend="envelope-from-address">$envelope_from_address</link>,
  <link linkend="from">$from</link>,
  <link linkend="sendmail">$sendmail</link>,
  <link linkend="smtp-url">$smtp_url</link>,
  <link linkend="pgp-sign-as">$pgp_sign_as</link>,
  <link linkend="smime-sign-as">$smime_sign_as</link>, and
  <link linkend="smime-encrypt-with">$smime_encrypt_with</link>.
  It's not feasible to backup all variables, but if you believe
  we've missed an important setting, please let the developers know.
</para>
<para>
  To help prevent forgetting about backgrounded sessions, <link
  linkend="background-confirm-quit">$background_confirm_quit</link>
  will prompt before exiting, in addition to <link
  linkend="quit">$quit</link>.  Additionally, the <literal>%B</literal>
  expando in <link linkend="status-format">$status_format</link>
  displays the number of backgrounded compose sessions.
</para>
<para>
  Background editing is available for most, but not all, message
  composition in Mutt.  Sending from the command line disables
  background editing, because there is no index to return to.
</para>
</sect2>


</sect1>

<sect1 id="forwarding-mail">
<title>Forwarding and Bouncing Mail</title>

<para>
Bouncing and forwarding let you send an existing message to recipients
that you specify. Bouncing a message sends a verbatim copy of a message
to alternative addresses as if they were the message's original
recipients specified in the Bcc header.  Forwarding a message, on the
other hand, allows you to modify the message before it is resent (for
example, by adding your own comments). Bouncing is done using the
<literal>&lt;bounce&gt;</literal> function and forwarding using the
<literal>&lt;forward&gt;</literal> function bound to <quote>b</quote>
and <quote>f</quote> respectively.
</para>

<para>
Forwarding can be done by including the original message in the new
message's body (surrounded by indicating lines) or including it as a
MIME attachment, depending on the value of the <link
linkend="mime-forward">$mime_forward</link> variable.  Decoding of
attachments, like in the pager, can be controlled by the <link
linkend="forward-decode">$forward_decode</link> and <link
linkend="mime-forward-decode">$mime_forward_decode</link> variables,
respectively.  The desired forwarding format may depend on the content,
therefore <link linkend="mime-forward">$mime_forward</link> is a
quadoption which, for example, can be set to <quote>ask-no</quote>.
</para>

<para>
Mutt's default (<link
linkend="mime-forward">$mime_forward</link>=<quote>no</quote> and
<link
linkend="forward-decode">$forward_decode</link>=<quote>yes</quote>) is
to use standard inline forwarding.  In that mode all text-decodable
parts are included in the new message body.  Other attachments from
the original email can also be attached to the new message, based on the
quadoption <link
linkend="forward-attachments">$forward_attachments</link>.
</para>

<para>
The inclusion of headers is controlled by the current setting of the
<link linkend="weed">$weed</link> variable, unless <link
linkend="mime-forward">$mime_forward</link> is set.
</para>

<para>
Editing the message to forward follows the same procedure as sending or
replying to a message does, but can be disabled via the quadoption
<link linkend="forward-edit">$forward_edit</link>.
</para>

</sect1>

<sect1 id="postponing-mail">
<title>Postponing Mail</title>

<para>
At times it is desirable to delay sending a message that you have
already begun to compose.  When the
<literal>&lt;postpone-message&gt;</literal> function is used in the
<emphasis>compose</emphasis> menu, the body of your message and
attachments are stored in the mailbox specified by the <link
linkend="postponed">$postponed</link> variable.  This means that you can
recall the message even if you exit Mutt and then restart it at a later
time.
</para>

<para>
Once a message is postponed, there are several ways to resume it.  From
the command line you can use the <quote>-p</quote> option, or if you
compose a new message from the <emphasis>index</emphasis> or
<emphasis>pager</emphasis> you will be prompted if postponed messages
exist.  If multiple messages are currently postponed, the
<emphasis>postponed</emphasis> menu will pop up and you can select which
message you would like to resume.
</para>

<note>
<para>
If you postpone a reply to a message, the reply setting of the message
is only updated when you actually finish the message and send it.  Also,
you must be in the same folder with the message you replied to for the
status of the message to be updated.
</para>
</note>

<para>
See also the <link linkend="postpone">$postpone</link> quad-option.
</para>

</sect1>

<sect1 id="encryption">
<title>Encryption and Signing</title>

<para>
OpenPGP and S/MIME are enabled in one of two ways: <quote>classic
mode</quote> or GPGME.  The former invokes external programs to
perform the various operations; it is better tested and more
flexible, but requires some configuration.  The latter uses the
GnuPG project's GPGME library.
</para>

<para>
To enable <quote>classic mode</quote>, ensure GPGME is disabled and
use the <literal>gpg.rc</literal> or <literal>smime.rc</literal> files
that come with mutt.  These are typically installed under
<literal>/usr/local/share/doc/mutt/samples/</literal>.  Source them, either
directly or by copying them to your .mutt directory and sourcing them.
Sourcing them directly from
<literal>/usr/local/share/doc/mutt/samples/</literal> has the benefit of
automatically using fixes and security improvements to the command
invocations, and is recommended.
</para>

<screen>
unset crypt_use_gpgme
source /usr/local/share/doc/mutt/samples/gpg.rc
source /usr/local/share/doc/mutt/samples/smime.rc
</screen>

<para>
To use GPGME instead, simply ensure the option is enabled in your .muttrc:
</para>

<screen>
set crypt_use_gpgme
</screen>

<sect2 id="enc-pgp">
<title>OpenPGP Configuration</title>

<para>
The two most important settings are <link
linkend="pgp-default-key">$pgp_default_key</link> and <link
linkend="pgp-sign-as">$pgp_sign_as</link>.  To perform encryption, you
must set the first variable.  If you have a separate signing key, or
only have a signing key, then set the second.  Most people will only
need to set <link linkend="pgp-default-key">$pgp_default_key</link>.
</para>

<para>
Starting with version 2.1.0, GnuPG automatically uses an
<literal>agent</literal> to prompt for your passphrase.  If you are
using a version older than that, you'll need to ensure an agent is
running (alternatively, you can unset <link
linkend="pgp-use-gpg-agent">$pgp_use_gpg_agent</link> and Mutt will
prompt you for your passphrase).  The agent in turn uses a
<literal>pinentry</literal> program to display the prompt.  There are
many different kinds of pinentry programs that can be used: qt, gtk2,
gnome3, fltk, and curses.  However, Mutt does <emphasis>not</emphasis>
work properly with the tty pinentry program.  Please ensure you have
one of the GUI or curses pinentry programs installed and configured to
be the default for your system.
</para>
</sect2>

<sect2 id="enc-smime">
<title>S/MIME Configuration</title>

<para>
As with OpenPGP, the two most important settings are <link
linkend="smime-default-key">$smime_default_key</link> and <link
linkend="smime-sign-as">$smime_sign_as</link>.  To perform encryption
and decryption, you must set the first variable.  If you have a
separate signing key, or only have a signing key, then set the second.
Most people will only need to set <link
linkend="smime-default-key">$smime_default_key</link>.
</para>

<para>
In <quote>classic mode</quote>, keys and certificates are managed by
the <literal>smime_keys</literal> program that comes with Mutt.  By
default they are stored under <literal>~/.smime/</literal>. (This is
set by the <literal>smime.rc</literal> file with <link
linkend="smime-certificates">$smime_certificates</link> and <link
linkend="smime-keys">$smime_keys</link>.)  To initialize this
directory, use the command <quote><literal>smime_keys
init</literal></quote> from a shell prompt.  The program can be then
be used to import and list certificates.  You may also want to
periodically run <quote><literal>smime_keys refresh</literal></quote>
to update status flags for your certificates.
</para>
</sect2>

</sect1>

</chapter>

<chapter id="configuration">
<title>Configuration</title>

<sect1 id="configuration-files">
<title>Location of Initialization Files</title>

<para>
While the default configuration (or <quote>preferences</quote>) make
Mutt usable right out of the box, it is often desirable to tailor Mutt
to suit your own tastes. When Mutt is first invoked, it will attempt to
read the <quote>system</quote> configuration file (defaults set by your
local system administrator), unless the <quote>-n</quote> <link
linkend="commandline">command line</link> option is specified.  This
file is typically <literal>/usr/local/share/mutt/Muttrc</literal> or
<literal>/etc/Muttrc</literal>. Mutt will next look for a file named
<literal>.muttrc</literal> in your home directory.  If this file does
not exist and your home directory has a subdirectory named
<literal>.mutt</literal>, Mutt tries to load a file named
<literal>.mutt/muttrc</literal>.  If still not found, Mutt will try
<literal>$XDG_CONFIG_HOME/mutt/muttrc</literal>.
</para>

<para>
<literal>.muttrc</literal> is the file where you will usually place your
<link linkend="commands">commands</link> to configure Mutt.
</para>

<para>
In addition, Mutt supports version specific configuration files that are
parsed instead of the default files as explained above.  For instance,
if your system has a <literal>Muttrc-0.88</literal> file in the system
configuration directory, and you are running version 0.88 of Mutt, this
file will be sourced instead of the <literal>Muttrc</literal> file.  The
same is true of the user configuration file, if you have a file
<literal>.muttrc-0.88.6</literal> in your home directory, when you run
Mutt version 0.88.6, it will source this file instead of the default
<literal>.muttrc</literal> file.  The version number is the same which
is visible using the <quote>-v</quote> <link
linkend="commandline">command line</link> switch or using the
<literal>show-version</literal> key (default: V) from the index menu.
</para>

</sect1>

<sect1 id="quickconfig">
<title>Starter Muttrc</title>

<para>
Mutt is highly configurable because it's <emphasis>meant</emphasis> to
be customized to your needs and preferences.  However, this
configurability can make it difficult when just getting started.  A
few sample muttrc files come with mutt, under
<literal>doc/mutt/samples/</literal>.  Among them, <ulink
url="https://gitlab.com/muttmua/mutt/tree/master/contrib/sample.muttrc-starter"
>sample.muttrc-starter</ulink> is a basic example config with a few
suggested settings and pointers to useful programs.
</para>
</sect1>

<sect1 id="muttrc-syntax" xreflabel="Syntax of Initialization Files">
<title>Syntax of Initialization Files</title>

<para>
An initialization file consists of a series of <link
linkend="commands">commands</link>.  Each line of the file may contain
one or more commands.  When multiple commands are used, they must be
separated by a semicolon (<quote>;</quote>).
</para>

<example id="ex-rc-multiple-cmds">
<title>Multiple configuration commands per line</title>
<screen>
set realname='Mutt user' ; ignore x-
</screen>
</example>

<para>
The hash mark, or pound sign (<quote>#</quote>), is used as a
<quote>comment</quote> character. You can use it to annotate your
initialization file. All text after the comment character to the end of
the line is ignored.
</para>

<example id="ex-ec-comment">
<title>Commenting configuration files</title>
<screen>
my_hdr X-Disclaimer: Why are you listening to me? <emphasis role="comment"># This is a comment</emphasis>
</screen>
</example>

<para>
Single quotes (<quote>'</quote>) and double quotes (<quote>"</quote>)
can be used to quote strings which contain spaces or other special
characters.  The difference between the two types of quotes is similar
to that of many popular shell programs, namely that a single quote is
used to specify a literal string (one that is not interpreted for shell
variables or quoting with a backslash [see next paragraph]), while
double quotes indicate a string for which should be evaluated.  For
example, backticks are evaluated inside of double quotes, but
<emphasis>not</emphasis> for single quotes.
</para>

<para>
<quote>\</quote> quotes the next character, just as in shells such as
bash and zsh.  For example, if want to put quotes <quote>"</quote>
inside of a string, you can use <quote>\</quote> to force the next
character to be a literal instead of interpreted character.
</para>

<example id="ex-rc-quote">
<title>Escaping quotes in configuration files</title>
<screen>
set realname="Michael \"MuttDude\" Elkins"
</screen>
</example>

<para>
<quote>\\</quote> means to insert a literal <quote>\</quote> into the line.
<quote>\n</quote> and <quote>\r</quote> have their usual C meanings of linefeed and
carriage-return, respectively.
</para>

<para>
A <quote>\</quote> at the end of a line can be used to split commands
over multiple lines as it <quote>escapes</quote> the line end, provided
that the split points don't appear in the middle of command names. Lines
are first concatenated before interpretation so that a multi-line can be
commented by commenting out the first line only.
</para>

<example id="ex-rc-split">
<title>Splitting long configuration commands over several lines</title>
<screen>
set status_format="some very \
long value split \
over several lines"
</screen>
</example>

<para>
It is also possible to substitute the output of a Unix command in an
initialization file.  This is accomplished by enclosing the command in
backticks (``). In <xref linkend="ex-rc-backtick"/>, the output of the
Unix command <quote>uname -a</quote> will be substituted before the line
is parsed.  Since initialization files are line oriented, only the first
line of output from the Unix command will be substituted.
</para>

<example id="ex-rc-backtick">
<title>Using external command's output in configuration files</title>
<screen>
my_hdr X-Operating-System: `uname -a`
</screen>
</example>

<para>
To avoid the output of backticks being parsed, place them inside
double quotes.  In <xref linkend="ex-backtick-dblquotes"/>, the output
of the gpg decryption is assigned directly to $imap_pass, so that
special characters in the password (e.g.<quote>'</quote>,
<quote>#</quote>, <quote>$</quote>) are not parsed and interpreted
specially by mutt.
</para>

<example id="ex-backtick-dblquotes">
<title>Preventing the output of backticks from being parsed</title>
<screen>
set imap_pass="`gpg --batch -q --decrypt ~/.mutt/account.gpg`"
</screen>
</example>

<para>
Both environment variables and Mutt variables can be accessed by
prepending <quote>$</quote> to the name of the variable. For example,
</para>

<example id="ex-rc-env">
<title>Using environment variables in configuration files</title>
<screen>
set record=+sent_on_$HOSTNAME
</screen>
</example>

<para>
will cause Mutt to save outgoing messages to a folder named
<quote>sent_on_kremvax</quote> if the environment variable
<literal>$HOSTNAME</literal> is set to <quote>kremvax.</quote> (See
<link linkend="record">$record</link> for details.)
</para>

<para>
Mutt expands the variable when it is assigned, not when it is used. If
the value of a variable on the right-hand side of an assignment changes
after the assignment, the variable on the left-hand side will not be
affected.
</para>

<para>
If <link linkend="muttlisp-inline-eval">$muttlisp_inline_eval</link> is set, an unquoted
parenthesis-enclosed expression will be evaluated as MuttLisp.  See the
<link linkend="muttlisp">Using MuttLisp</link> section for more details.
</para>

<example id="ex-rc-muttlisp">
<title>Using MuttLisp expresions</title>
<screen>
set signature = \
  (if (equal $my_name "Kevin McCarthy") ~/kevin.sig ~/other.sig)
</screen>
</example>

<para>
The commands understood by Mutt are explained in the next paragraphs.
For a complete list, see the <link linkend="commands">command
reference</link>.
</para>

<para>
All configuration files are expected to be in the current locale as
specified by the <link linkend="charset">$charset</link> variable which
doesn't have a default value since it's determined by Mutt at startup.
If a configuration file is not encoded in the same character set the
<link linkend="config-charset">$config_charset</link> variable should be
used: all lines starting with the next are recoded from <link
linkend="config-charset">$config_charset</link> to <link
linkend="charset">$charset</link>.
</para>

<para>
This mechanism should be avoided if possible as it has the following
implications:
</para>

<itemizedlist>

<listitem><para>These variables should be set early in a configuration
file with <link linkend="charset">$charset</link> preceding <link
linkend="config-charset">$config_charset</link> so Mutt knows what
character set to convert to.</para></listitem>

<listitem><para>If <link linkend="config-charset">$config_charset</link>
is set, it should be set in each configuration file because the value is
global and <emphasis>not</emphasis> per configuration
file.</para></listitem>

<listitem><para>Because Mutt first recodes a line before it attempts to
parse it, a conversion introducing question marks or other characters as
part of errors (unconvertable characters, transliteration) may introduce
syntax errors or silently change the meaning of certain tokens
(e.g. inserting question marks into regular
expressions).</para></listitem>

</itemizedlist>

</sect1>

<sect1 id="addrgroup">
<title>Address Groups</title>

<para>Usage:</para>

<cmdsynopsis>
<command>group</command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable class="parameter">name</replaceable>
</arg>
<group choice="req">
<arg choice="plain" rep="repeat">
<option>-rx</option>
<replaceable class="parameter">expr</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<option>-addr</option>
<replaceable class="parameter">expr</replaceable>
</arg>
</group>

<command>ungroup</command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable class="parameter">name</replaceable>
</arg>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<option>-rx</option>
<replaceable class="parameter">expr</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<option>-addr</option>
<replaceable class="parameter">expr</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
Mutt supports grouping addresses logically into named groups. An address
or address pattern can appear in several groups at the same time. These
groups can be used in <link linkend="patterns">patterns</link> (for searching, limiting and tagging) and
in hooks by using group patterns. This can be useful to classify mail
and take certain actions depending on in what groups the message is.
For example, the mutt user's mailing list would fit into the categories
<quote>mailing list</quote> and <quote>mutt-related</quote>. Using <link
linkend="send-hook"><literal>send-hook</literal></link>, the sender can
be set to a dedicated one for writing mailing list messages, and the
signature could be set to a mutt-related one for writing to a mutt list
&mdash; for other lists, the list sender setting still applies but a
different signature can be selected. Or, given a group only containing
recipients known to accept encrypted mail,
<quote>auto-encryption</quote> can be achieved easily.
</para>

<para>
The <command>group</command> command is used to directly add either
addresses or regular expressions to the specified group or groups. The
different categories of arguments to the <command>group</command>
command can be in any order. The flags <literal>-rx</literal> and
<literal>-addr</literal> specify what the following strings (that cannot
begin with a hyphen) should be interpreted as: either a regular
expression or an email address, respectively.
</para>

<para>
These address groups can also be created implicitly by the <link
linkend="alias"><command>alias</command></link>, <link
linkend="lists"><command>lists</command></link>, <link
linkend="lists"><command>subscribe</command></link> and <link
linkend="alternates"><command>alternates</command></link> commands by
specifying the optional <literal>-group</literal> option. For example,
</para>

<screen>
alternates -group me address1 address2
alternates -group me -group work address3
</screen>

<para>
would create a group named <quote>me</quote> which contains all your
addresses and a group named <quote>work</quote> which contains only your
work address <emphasis>address3</emphasis>. Besides many other
possibilities, this could be used to automatically mark your own
messages in a mailing list folder as read or use a special signature for
work-related messages.
</para>

<para>
The <command>ungroup</command> command is used to remove addresses or
regular expressions from the specified group or groups. The syntax is
similar to the <command>group</command> command, however the special
character <literal>*</literal> can be used to empty a group of all of
its contents. As soon as a group gets empty because all addresses and
regular expressions have been removed, it'll internally be removed, too
(i.e. there cannot be an empty group). When removing regular expressions
from a group, the pattern must be specified exactly as given to the
<command>group</command> command or <literal>-group</literal> argument.
</para>

</sect1>

<sect1 id="alias">
<title>Defining/Using Aliases</title>

<para>Usage:</para>

<cmdsynopsis>
<command>alias</command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable class="parameter">name</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">key</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">address</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">address</replaceable>
</arg>

<command>unalias</command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable>name</replaceable>
</arg>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">key</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
It's usually very cumbersome to remember or type out the address of
someone you are communicating with.  Mutt allows you to create
<quote>aliases</quote> which map a short string to a full address.
</para>

<note>
<para>
If you want to create an alias for more than one address, you
<emphasis>must</emphasis> separate the addresses with a comma
(<quote>,</quote>).
</para>
</note>

<para>
The optional <literal>-group</literal> argument to
<command>alias</command> causes the aliased address(es) to be added to
the named <emphasis>group</emphasis>.
</para>

<para>
To add an alias:
</para>

<screen>
alias muttdude me@cs.hmc.edu (Michael Elkins)
alias theguys manny, moe, jack
</screen>

<para>
To remove an alias or aliases (<quote>*</quote> means all aliases):
</para>

<screen>
unalias muttdude
unalias *
</screen>

<para>
Unlike other mailers, Mutt doesn't require aliases to be defined in a
special file.  The <command>alias</command> command can appear anywhere
in a configuration file, as long as this file is <link
linkend="source"><command>source</command>d</link>.  Consequently, you
can have multiple alias files, or you can have all aliases defined in
your <literal>.muttrc</literal>.
</para>

<para>
On the other hand, the <link
linkend="create-alias"><literal>&lt;create-alias&gt;</literal></link>
function can use only one file, the one pointed to by the <link
linkend="alias-file">$alias_file</link> variable (which is
<literal>~/.muttrc</literal> by default). This file is not special
either, in the sense that Mutt will happily append aliases to any file,
but in order for the new aliases to take effect you need to explicitly
<link linkend="source"><command>source</command></link> this file too.
</para>

<example id="ex-alias-external">
<title>Configuring external alias files</title>
<screen>
source /usr/local/share/Mutt.aliases
source ~/.mail_aliases
set alias_file=~/.mail_aliases
</screen>
</example>

<para>
To use aliases, you merely use the alias at any place in Mutt where Mutt
prompts for addresses, such as the <emphasis>To:</emphasis> or
<emphasis>Cc:</emphasis> prompt.  You can also enter aliases in your
editor at the appropriate headers if you have the <link
linkend="edit-headers">$edit_headers</link> variable set.
</para>

<para>
In addition, at the various address prompts, you can use the tab
character to expand a partial alias to the full alias.  If there are
multiple matches, Mutt will bring up a menu with the matching aliases.
In order to be presented with the full list of aliases, you must hit tab
without a partial alias, such as at the beginning of the prompt or after
a comma denoting multiple addresses.
</para>

<para>
In the alias menu, you can select as many aliases as you want with the
<literal>select-entry</literal> key (default: &lt;Return&gt;), and use
the <emphasis>exit</emphasis> key (default: q) to return to the address
prompt.
</para>

</sect1>

<sect1 id="bind">
<title>Changing the Default Key Bindings</title>

<para>Usage:</para>

<cmdsynopsis>
<command>bind</command>
<arg choice="plain">
<replaceable class="parameter">map</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">key</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">function</replaceable>
</arg>
</cmdsynopsis>

<para>
This command allows you to change the default key bindings (operation
invoked when pressing a key).
</para>

<para>
<emphasis>map</emphasis> specifies in which menu the binding belongs.
Multiple maps may be specified by separating them with commas (no
additional whitespace is allowed). The currently defined maps are:
</para>

<anchor id="maps"/>
<variablelist>

<varlistentry>
<term>generic</term>
<listitem>
<para>
This is not a real menu, but is used as a fallback for all of the other
menus except for the pager and editor modes.  If a key is not defined in
another menu, Mutt will look for a binding to use in this menu.  This
allows you to bind a key to a certain function in multiple menus instead
of having multiple <command>bind</command> statements to accomplish the
same task.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>alias</term>
<listitem>
<para>
The alias menu is the list of your personal aliases as defined in your
<literal>.muttrc</literal>.  It is the mapping from a short alias name
to the full email address(es) of the recipient(s).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>attach</term>
<listitem>
<para>
The attachment menu is used to access the attachments on received
messages.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>browser</term>
<listitem>
<para>
The browser is used for both browsing the local directory structure, and
for listing all of your incoming mailboxes.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>editor</term>
<listitem>
<para>
The editor is used to allow the user to enter a single line of text, such as
the <emphasis>To</emphasis> or <emphasis>Subject</emphasis> prompts in the
<literal>compose</literal> menu.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>index</term>
<listitem>
<para>
The index is the list of messages contained in a mailbox.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>compose</term>
<listitem>
<para>
The compose menu is the screen used when sending a new message.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>pager</term>
<listitem>
<para>
The pager is the mode used to display message/attachment data, and help
listings.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>pgp</term>
<listitem>
<para>
The pgp menu is used to select the OpenPGP keys used to encrypt outgoing
messages.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>smime</term>
<listitem>
<para>
The smime menu is used to select the OpenSSL certificates used to
encrypt outgoing messages.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>postpone</term>
<listitem>
<para>
The postpone menu is similar to the index menu, except is used when
recalling a message the user was composing, but saved until later.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>query</term>
<listitem>
<para>
The query menu is the browser for results returned by <link
linkend="query-command">$query_command</link>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>mix</term>
<listitem>
<para>
The mixmaster screen is used to select remailer options for outgoing
messages (if Mutt is compiled with Mixmaster support).
</para>
</listitem>
</varlistentry>
</variablelist>

<para>
<emphasis>key</emphasis> is the key (or key sequence) you wish to bind.
To specify a control character, use the sequence
<emphasis>\Cx</emphasis>, where <emphasis>x</emphasis> is the letter of
the control character (for example, to specify control-A use
<quote>\Ca</quote>).  Note that the case of <emphasis>x</emphasis> as
well as <emphasis>\C</emphasis> is ignored, so that
<emphasis>\CA</emphasis>, <emphasis>\Ca</emphasis>,
<emphasis>\cA</emphasis> and <emphasis>\ca</emphasis> are all
equivalent.  An alternative form is to specify the key as a three digit
octal number prefixed with a <quote>\</quote> (for example
<emphasis>\177</emphasis> is equivalent to <emphasis>\c?</emphasis>). In
addition, <emphasis>key</emphasis> may be a symbolic name as shown in
<xref linkend="tab-key-names"/>.
</para>

<table id="tab-key-names">
<title>Symbolic key names</title>
<tgroup cols="2">
<thead>
<row><entry>Symbolic name</entry><entry>Meaning</entry></row>
</thead>
<tbody>
<row><entry>\t</entry><entry>tab</entry></row>
<row><entry>&lt;tab&gt;</entry><entry>tab</entry></row>
<row><entry>&lt;backtab&gt;</entry><entry>backtab / shift-tab</entry></row>
<row><entry>\r</entry><entry>carriage return</entry></row>
<row><entry>\n</entry><entry>newline</entry></row>
<row><entry>\e</entry><entry>escape</entry></row>
<row><entry>&lt;esc&gt;</entry><entry>escape</entry></row>
<row><entry>&lt;up&gt;</entry><entry>up arrow</entry></row>
<row><entry>&lt;down&gt;</entry><entry>down arrow</entry></row>
<row><entry>&lt;left&gt;</entry><entry>left arrow</entry></row>
<row><entry>&lt;right&gt;</entry><entry>right arrow</entry></row>
<row><entry>&lt;pageup&gt;</entry><entry>Page Up</entry></row>
<row><entry>&lt;pagedown&gt;</entry><entry>Page Down</entry></row>
<row><entry>&lt;backspace&gt;</entry><entry>Backspace</entry></row>
<row><entry>&lt;delete&gt;</entry><entry>Delete</entry></row>
<row><entry>&lt;insert&gt;</entry><entry>Insert</entry></row>
<row><entry>&lt;enter&gt;</entry><entry>Enter</entry></row>
<row><entry>&lt;return&gt;</entry><entry>Return</entry></row>
<row><entry>&lt;home&gt;</entry><entry>Home</entry></row>
<row><entry>&lt;end&gt;</entry><entry>End</entry></row>
<row><entry>&lt;space&gt;</entry><entry>Space bar</entry></row>
<row><entry>&lt;f1&gt;</entry><entry>function key 1</entry></row>
<row><entry>&lt;f10&gt;</entry><entry>function key 10</entry></row>
</tbody>
</tgroup>
</table>

<para>
The <literal>&lt;what-key&gt;</literal> function can be used to
explore keycode and symbolic names for other keys on your keyboard.
Executing this function will display information about each key
pressed, until terminated by <literal>^G</literal>.
</para>

<para>
<emphasis>key</emphasis> does not need to be enclosed in quotes unless
it contains a space (<quote>&nbsp;</quote>) or semi-colon
(<quote>;</quote>).
</para>

<para>
<emphasis>function</emphasis> specifies which action to take when
<emphasis>key</emphasis> is pressed.  For a complete list of functions,
see the <link linkend="functions">reference</link>. Note that the
<command>bind</command> expects <emphasis>function</emphasis> to be
specified without angle brackets.
</para>

<para>
The special function <literal>&lt;noop&gt;</literal> unbinds the
specified key sequence.
</para>

<sect2 id="stty">
  <title>Terminal Keybindings</title>

  <para>
    Some key bindings are controlled by the terminal, and so by
    default can't be bound inside Mutt.  These may include
    <literal>^C</literal>, <literal>^\</literal>, <literal>^Q</literal>,
    <literal>^S</literal>, <literal>^Z</literal>, and on BSD/Mac
    <literal>^Y</literal>.  These terminal settings can be viewed and
    changed using the <literal>stty</literal> program.
  </para>
  <para>
    <quote><literal>stty -a</literal></quote> will list the bound
    characters (not all of them affect Mutt), and what actions they
    take when pressed.  For example,
    you may see <quote><literal>intr = ^C</literal></quote> in its
    output.  This means typing <literal>^C</literal> will send an
    interrupt signal.  <quote><literal>quit = ^\</literal></quote>
    means typing <literal>^\</literal> (commonly also
    <literal>^4</literal>) will send a quit signal.
  </para>
  <para>
    To unbind a key from an action, you invoke <quote>stty action
    undef</quote>.  For example, <quote><literal>stty quit
    undef</literal></quote> will unbind <literal>^\</literal> (and
    <literal>^4</literal>) from sending the quit signal.  Once unbound
    (e.g, by placing that line in your .bashrc, or in a Mutt wrapper
    script/function) you can use the key sequence in your Mutt
    bindings.
  </para>
</sect2>

</sect1>

<sect1 id="cd">
<title>Changing the current working directory</title>

<para>Usage:</para>

<cmdsynopsis>
<command>cd</command>
<arg choice="plain">
<replaceable class="parameter">directory</replaceable>
</arg>
</cmdsynopsis>

<para>
The <literal>cd</literal> command changes Mutt's current working directory.
This affects commands and functions like <literal>source</literal>,
<literal>change-folder</literal>, and <literal>save-entry</literal> that use
relative paths. Using <literal>cd</literal> without directory changes to your
home directory.
</para>

</sect1>

<sect1 id="charset-hook">
<title>Defining Aliases for Character Sets</title>

<para>Usage:</para>

<cmdsynopsis>
<command>charset-hook</command>
<arg choice="plain">
<replaceable class="parameter">alias</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">charset</replaceable>
</arg>

<command>iconv-hook</command>
<arg choice="plain">
<replaceable class="parameter">charset</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">local-charset</replaceable>
</arg>
</cmdsynopsis>

<para>
The <command>charset-hook</command> command defines an alias for a
character set.  This is useful to properly display messages which are
tagged with a character set name not known to Mutt.
</para>

<para>
The <command>iconv-hook</command> command defines a system-specific name
for a character set.  This is helpful when your systems character
conversion library insists on using strange, system-specific names for
character sets.
</para>

</sect1>

<sect1 id="folder-hook">
<title>Setting Variables Based Upon Mailbox</title>

<para>Usage:</para>

<cmdsynopsis>
<command>folder-hook</command>
<arg choice="plain">
<replaceable class="parameter">[!]regexp</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">command</replaceable>
</arg>
</cmdsynopsis>

<para>
It is often desirable to change settings based on which mailbox you are
reading.  The <command>folder-hook</command> command provides a method
by which you can execute any configuration command.
<emphasis>regexp</emphasis> is a regular expression specifying in which
mailboxes to execute <emphasis>command</emphasis> before loading.  If a
mailbox matches multiple <command>folder-hook</command>s, they are
executed in the order given in the <literal>.muttrc</literal>.
</para>

<para>
The regexp parameter has <link linkend="shortcuts">mailbox
shortcut</link> expansion performed on the first character.
See  <xref linkend="mailbox-hook"/> for more details.
</para>

<note>
<para>
If you use the <quote>!</quote> shortcut for <link
linkend="spoolfile">$spoolfile</link> at the beginning of the pattern,
you must place it inside of double or single quotes in order to
distinguish it from the logical <emphasis>not</emphasis> operator for
the expression.
</para>
</note>

<note>
<para>
Settings are <emphasis>not</emphasis> restored when you leave the
mailbox.  For example, a command action to perform is to change the
sorting method based upon the mailbox being read:
</para>

<screen>
folder-hook mutt "set sort=threads"</screen>

<para>
However, the sorting method is not restored to its previous value when
reading a different mailbox.  To specify a <emphasis>default</emphasis>
command, use the pattern <quote>.</quote> before other
<command>folder-hook</command>s adjusting a value on a per-folder basis
because <command>folder-hook</command>s are evaluated in the order given
in the configuration file.
</para>
</note>

<note>
<para>
The keyboard buffer will not be processed until after all hooks
are run; multiple <link linkend="push">push</link> or <link
linkend="exec">exec</link> commands will end up being processed in
reverse order.
</para>
</note>

<para>
The following example will set the <link linkend="sort">sort</link>
variable to <literal>date-sent</literal> for all folders but to
<literal>threads</literal> for all folders containing
<quote>mutt</quote> in their name.
</para>

<example id="ex-folder-sorting">
<title>Setting sort method based on mailbox name</title>
<screen>
folder-hook . "set sort=date-sent"
folder-hook mutt "set sort=threads"
</screen>
</example>

</sect1>

<sect1 id="macro">
<title>Keyboard Macros</title>

<para>Usage:</para>

<cmdsynopsis>
<command>macro</command>
<arg choice="plain">
<replaceable class="parameter">menu</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">key</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">sequence</replaceable>
</arg>
<arg choice="opt">
<replaceable class="parameter">description</replaceable>
</arg>
</cmdsynopsis>

<para>
Macros are useful when you would like a single key to perform a series
of actions.  When you press <emphasis>key</emphasis> in menu
<emphasis>menu</emphasis>, Mutt will behave as if you had typed
<emphasis>sequence</emphasis>.  So if you have a common sequence of
commands you type, you can create a macro to execute those commands with
a single key or fewer keys.
</para>

<para>
<emphasis>menu</emphasis> is the <link linkend="maps">map</link> which
the macro will be bound in.  Multiple maps may be specified by
separating multiple menu arguments by commas. Whitespace may not be used
in between the menu arguments and the commas separating them.
</para>

<para>
<emphasis>key</emphasis> and <emphasis>sequence</emphasis> are expanded
by the same rules as the <link linkend="bind">key bindings</link> with
some additions.  The first is that control characters in
<emphasis>sequence</emphasis> can also be specified as
<emphasis>^x</emphasis>.  In order to get a caret (<quote>^</quote>) you
need to use <emphasis>^^</emphasis>.  Secondly, to specify a certain key
such as <emphasis>up</emphasis> or to invoke a function directly, you
can use the format <emphasis>&lt;key name&gt;</emphasis> and
<emphasis>&lt;function name&gt;</emphasis>.  For a listing of key names
see the section on <link linkend="bind">key bindings</link>.  Functions
are listed in the <link linkend="functions">reference</link>.
</para>

<para>
The advantage with using function names directly is that the macros will
work regardless of the current key bindings, so they are not dependent
on the user having particular key definitions.  This makes them more
robust and portable, and also facilitates defining of macros in files
used by more than one user (e.g., the system Muttrc).
</para>

<para>
Optionally you can specify a descriptive text after
<emphasis>sequence</emphasis>, which is shown in the help screens if
they contain a description.
</para>

<note>
<para>
Macro definitions (if any) listed in the help screen(s), are
silently truncated at the screen width, and are not wrapped.
</para>
</note>

</sect1>

<sect1 id="color">
<title>Using Color and Mono Video Attributes</title>

<para>Usage:</para>

<cmdsynopsis>
<command>color</command>
<arg choice="plain">
<replaceable class="parameter">object</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">attribute</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">foreground</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">background</replaceable>
</arg>

<command>color</command>
<group choice="req">
<arg choice="plain">
<option>header</option>
</arg>
<arg choice="plain">
<option>body</option>
</arg>
</group>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">attribute</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">foreground</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">background</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">regexp</replaceable>
</arg>

<command>color</command>
<arg choice="plain">
<option>index</option>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">attribute</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">foreground</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">background</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>

<command>color</command>
<arg choice="plain">
<option>compose</option>
</arg>
<arg choice="plain">
<replaceable class="parameter">composeobject</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">attribute</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">foreground</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">background</replaceable>
</arg>

<command>uncolor</command>
<group choice="req">
<arg choice="plain">
<option>index</option>
</arg>
<arg choice="plain">
<option>header</option>
</arg>
<arg choice="plain">
<option>body</option>
</arg>
</group>
<group choice="req">
<arg choice="plain">
<replaceable>*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable>pattern</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
If your terminal supports color, you can spice up Mutt by creating your
own color scheme.  To define the color of an object (type of
information), you must specify both a foreground color
<emphasis>and</emphasis> a background color (it is not possible to only
specify one or the other).
</para>

<para>
<emphasis>header</emphasis> and <emphasis>body</emphasis> match
<emphasis><link linkend="regexp">regexp</link></emphasis> in the
header/body of a message, <emphasis>index</emphasis> matches
<emphasis><link linkend="patterns">pattern</link></emphasis> in the
message index.  Note that IMAP server-side searches (=b, =B, =h) are
not supported for color index patterns.
</para>

<para>
When <link linkend="header-color-partial">$header_color_partial</link>
is unset (the default), a <emphasis>header</emphasis> matched by
<emphasis>regexp</emphasis> will have color applied to the entire header.
When set, color is applied only to the exact text matched by
<emphasis>regexp</emphasis>.
</para>

<para>
<emphasis>object</emphasis> can be one of:
</para>

<itemizedlist>
<listitem><para>attachment</para></listitem>
<listitem><para>bold (highlighting bold patterns in the body of messages)</para></listitem>
<listitem><para>error (error messages printed by Mutt)</para></listitem>
<listitem><para>hdrdefault (default color of the message header in the pager)</para></listitem>
<listitem><para>indicator (arrow or bar used to indicate the current item in a menu)</para></listitem>
<listitem><para>markers (the <quote>+</quote> markers at the beginning of wrapped lines in the pager)</para></listitem>
<listitem><para>message (informational messages)</para></listitem>
<listitem><para>normal</para></listitem>
<listitem><para>prompt</para></listitem>
<listitem><para>quoted (text matching <link linkend="quote-regexp">$quote_regexp</link> in the body of a message)</para></listitem>
<listitem><para>quoted1, quoted2, ..., quoted<emphasis>N</emphasis> (higher levels of quoting)</para></listitem>
<listitem><para>search (highlighting of words in the pager)</para></listitem>
<listitem><para>signature</para></listitem>
<listitem><para>status (mode lines used to display info about the mailbox or message)</para></listitem>
<listitem><para>tilde (the <quote>~</quote> used to pad blank lines in the pager)</para></listitem>
<listitem><para>tree (thread tree drawn in the message index and attachment menu)</para></listitem>
<listitem><para>underline (highlighting underlined patterns in the body of messages)</para></listitem>
</itemizedlist>

<para>
<emphasis>composeobject</emphasis> can be one of:
</para>

<itemizedlist>
<listitem><para>header</para></listitem>
<listitem><para>security_encrypt</para></listitem>
<listitem><para>security_sign</para></listitem>
<listitem><para>security_both</para></listitem>
<listitem><para>security_none</para></listitem>
</itemizedlist>

<para>
<emphasis>attribute</emphasis> can be one of the following:
</para>

<itemizedlist>
<listitem><para>none</para></listitem>
<listitem><para>bold</para></listitem>
<listitem><para>underline</para></listitem>
<listitem><para>reverse</para></listitem>
<listitem><para>standout</para></listitem>
</itemizedlist>

<para>
<emphasis>foreground</emphasis> and <emphasis>background</emphasis> can
be one of the following:
</para>

<itemizedlist>
<listitem><para>white</para></listitem>
<listitem><para>black</para></listitem>
<listitem><para>green</para></listitem>
<listitem><para>magenta</para></listitem>
<listitem><para>blue</para></listitem>
<listitem><para>cyan</para></listitem>
<listitem><para>yellow</para></listitem>
<listitem><para>red</para></listitem>
<listitem><para>default</para></listitem>
<listitem><para>color<emphasis>x</emphasis></para>
</listitem>
</itemizedlist>

<para>
The color name can optionally be prefixed with the keyword
<literal>bright</literal> or <literal>light</literal> to make the color
boldfaced or light (e.g., <literal>brightred</literal>). The precise
behavior depends on the terminal and its configuration. In particular,
the boldfaced/light difference and such background colors may be
available only for terminals configured with at least 16&nbsp;colors,
as specified by the <literal>$TERM</literal> environment variable.
</para>

<para>
If your terminal supports it, the special keyword
<emphasis>default</emphasis> can be used as a transparent color.  The
value <emphasis>brightdefault</emphasis> is also valid.  If Mutt is
linked against the <emphasis>S-Lang</emphasis> library, you also need to
set the <literal>$COLORFGBG</literal> environment variable to the
default colors of your terminal for this to work; for example (for
Bourne-like shells):
</para>

<screen>
set COLORFGBG="green;black"
export COLORFGBG
</screen>

<note>
<para>
The <emphasis>S-Lang</emphasis> library requires you to use the
<emphasis>lightgray</emphasis> and <emphasis>brown</emphasis> keywords
instead of <emphasis>white</emphasis> and <emphasis>yellow</emphasis>
when setting this variable.
</para>
</note>

<note>
<para>
The <command>uncolor</command> command can be applied to the index,
header and body objects only.  It removes entries from the list. You
<emphasis>must</emphasis> specify the same pattern specified in the
<command>color</command> command for it to be removed.  The pattern
<quote>*</quote> is a special token which means to clear the color list
of all entries.
</para>
</note>

<para>
Mutt also recognizes the keywords <emphasis>color0</emphasis>,
<emphasis>color1</emphasis>, ...,
<emphasis>color</emphasis><emphasis>N-1</emphasis>
(<emphasis>N</emphasis> being the number of colors supported by your
terminal).  This is useful when you remap the colors for your display
(for example by changing the color associated with
<emphasis>color2</emphasis> for your xterm), since color names may then
lose their normal meaning.
</para>

<anchor id="mono"/>
<para>
If your terminal does not support color, it is still possible change the
video attributes through the use of the <quote>mono</quote>
command. Usage:
</para>

<cmdsynopsis>
<command>mono</command>
<arg choice="plain">
<replaceable class="parameter">object</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">attribute</replaceable>
</arg>

<command>mono</command>
<group choice="req">
<arg choice="plain">
<option>header</option>
</arg>
<arg choice="plain">
<option>body</option>
</arg>
</group>
<arg choice="plain">
<replaceable class="parameter">attribute</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">regexp</replaceable>
</arg>

<command>mono</command>
<arg choice="plain">
<option>index</option>
</arg>
<arg choice="plain">
<replaceable class="parameter">attribute</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>

<command>mono</command>
<arg choice="plain">
<option>compose</option>
</arg>
<arg choice="plain">
<replaceable class="parameter">composeobject</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">attribute</replaceable>
</arg>

<command>unmono</command>
<group choice="req">
<arg choice="plain">
<option>index</option>
</arg>
<arg choice="plain">
<option>header</option>
</arg>
<arg choice="plain">
<option>body</option>
</arg>
</group>
<group choice="req">
<arg choice="plain">
<replaceable>*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable>pattern</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
For <emphasis>object</emphasis>, <emphasis>composeobject</emphasis>, and
<emphasis>attribute</emphasis>, see the <command>color</command> command.
</para>
</sect1>

<sect1 id="msg-hdr-display">
<title>Message Header Display</title>

<sect2 id="hdr-folding">
<title>Header Display</title>

<para>
When displaying a message in the pager, Mutt folds long header lines at
<link linkend="wrap">$wrap</link> columns. Though there're precise rules
about where to break and how, Mutt always folds headers using a tab for
readability. (Note that the sending side is not affected by this, Mutt
tries to implement standards compliant folding.)
</para>

</sect2>

<sect2 id="ignore">
<title>Selecting Headers</title>

<para>Usage:</para>

<cmdsynopsis>
<command>ignore</command>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">pattern</replaceable>
</arg>

<command>unignore</command>
<group choice="req">
<arg choice="plain">
<replaceable>*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable>pattern</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
Messages often have many header fields added by automatic processing
systems, or which may not seem useful to display on the screen.  This
command allows you to specify header fields which you don't normally
want to see in the pager.
</para>

<para>
You do not need to specify the full header field name.  For example,
<quote>ignore content-</quote> will ignore all header fields that begin
with the pattern <quote>content-</quote>. <quote>ignore *</quote> will
ignore all headers.
</para>

<para>
To remove a previously added token from the list, use the
<quote>unignore</quote> command.  The <quote>unignore</quote> command
will make Mutt display headers with the given pattern.  For example, if
you do <quote>ignore x-</quote> it is possible to <quote>unignore
x-mailer</quote>.
</para>

<para>
<quote>unignore *</quote> will remove all tokens from the ignore list.
</para>

<example id="ex-header-weeding">
<title>Header weeding</title>
<screen>
<emphasis role="comment"># Sven's draconian header weeding</emphasis>
ignore *
unignore from date subject to cc
unignore organization organisation x-mailer: x-newsreader: x-mailing-list:
unignore posted-to:
</screen>
</example>

</sect2>

<sect2 id="hdr-order">
<title>Ordering Displayed Headers</title>

<para>Usage:</para>

<cmdsynopsis>
<command>hdr_order</command>
<arg choice="plain">
<replaceable class="parameter">header</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">header</replaceable>
</arg>

<command>unhdr_order</command>
<group choice="req">
<arg choice="plain">
<replaceable>*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable>header</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
With the <command>hdr_order</command> command you can specify an order
in which Mutt will attempt to present these headers to you when viewing
messages.
</para>

<para>
<quote><command>unhdr_order</command> *</quote> will clear all previous
headers from the order list, thus removing the header order effects set
by the system-wide startup file.
</para>

<example id="ex-hdr-order">
<title>Configuring header display order</title>
<screen>
hdr_order From Date: From: To: Cc: Subject:
</screen>
</example>

</sect2>
</sect1>

<sect1 id="alternates">
<title>Alternative Addresses</title>

<para>Usage:</para>

<cmdsynopsis>
<command>alternates</command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable>name</replaceable>
</arg>
<arg choice="plain">
<replaceable>regexp</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable>regexp</replaceable>
</arg>

<command>unalternates</command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable>name</replaceable>
</arg>
<group choice="req">
<arg choice="plain">
<replaceable>*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable>regexp</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
With various functions, Mutt will treat messages differently, depending
on whether you sent them or whether you received them from someone else.
For instance, when replying to a message that you sent to a different
party, Mutt will automatically suggest to send the response to the
original message's recipients &mdash; responding to yourself won't make
much sense in many cases.  (See <link
linkend="reply-to">$reply_to</link>.)
</para>

<para>
Many users receive e-mail under a number of different addresses. To
fully use Mutt's features here, the program must be able to recognize
what e-mail addresses you receive mail under. That's the purpose of the
<command>alternates</command> command: It takes a list of regular
expressions, each of which can identify an address under which you
receive e-mail.
</para>

<para>
As addresses are matched using regular expressions and not exact strict
comparisons, you should make sure you specify your addresses as precise
as possible to avoid mismatches. For example, if you specify:
</para>

<screen>
alternates user@example
</screen>

<para>
Mutt will consider <quote><literal>some-user@example</literal></quote>
as being your address, too which may not be desired. As a solution, in
such cases addresses should be specified as:
</para>

<screen>
alternates '^user@example$'
</screen>

<para>
The <literal>-group</literal> flag causes all of the subsequent regular
expressions to be added to the named group.
</para>

<para>
The <command>unalternates</command> command can be used to write
exceptions to <command>alternates</command> patterns. If an address
matches something in an <command>alternates</command> command, but you
nonetheless do not think it is from you, you can list a more precise
pattern under an <command>unalternates</command> command.
</para>

<para>
To remove a regular expression from the <command>alternates</command>
list, use the <command>unalternates</command> command with exactly the
same <emphasis>regexp</emphasis>.  Likewise, if the
<emphasis>regexp</emphasis> for an <command>alternates</command> command
matches an entry on the <command>unalternates</command> list, that
<command>unalternates</command> entry will be removed. If the
<emphasis>regexp</emphasis> for <command>unalternates</command> is
<quote>*</quote>, <emphasis>all entries</emphasis> on
<command>alternates</command> will be removed.
</para>

</sect1>

<sect1 id="lists">
<title>Mailing Lists</title>

<anchor id="subscribe"/>
<para>Usage:</para>

<cmdsynopsis>
<command>lists</command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable class="parameter">name</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">regexp</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">regexp</replaceable>
</arg>

<command>unlists</command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">regexp</replaceable>
</arg>
</group>

<command>subscribe</command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable class="parameter">name</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">regexp</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">regexp</replaceable>
</arg>

<command>unsubscribe</command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">regexp</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
Mutt has a few nice features for <link linkend="using-lists">handling
mailing lists</link>.  In order to take advantage of them, you must
specify which addresses belong to mailing lists, and which mailing lists
you are subscribed to. Mutt also has limited support for auto-detecting
mailing lists: it supports parsing <literal>mailto:</literal> links in
the common <literal>List-Post:</literal> header which has the same
effect as specifying the list address via the <command>lists</command>
command (except the group feature). Once you have done this, the <link
linkend="list-reply"><literal>&lt;list-reply&gt;</literal></link>
function will work for all known lists.  Additionally, when you send a
message to a known list and <link
linkend="followup-to">$followup_to</link> is set, Mutt will add a
Mail-Followup-To header.  For unsubscribed lists, this will include
your personal address, ensuring you receive a copy of replies.  For
subscribed mailing lists, the header will not, telling other users'
mail user agents not to send copies of replies to your personal
address.
</para>

<note>
<para>
The Mail-Followup-To header is a non-standard extension which is not
supported by all mail user agents.  Adding it is not bullet-proof
against receiving personal CCs of list messages.  Also note that the
generation of the Mail-Followup-To header is controlled by the <link
linkend="followup-to">$followup_to</link> configuration variable since
it's common practice on some mailing lists to send Cc upon replies
(which is more a group- than a list-reply).
</para>
</note>

<para>
More precisely, Mutt maintains lists of patterns for the addresses of
known and subscribed mailing lists.  Every subscribed mailing list is
known. To mark a mailing list as known, use the <command>list</command>
command.  To mark it as subscribed, use <command>subscribe</command>.
</para>

<para>
You can use regular expressions with both commands. To mark all messages
sent to a specific bug report's address on Debian's bug tracking system
as list mail, for instance, you could say
</para>

<screen>
subscribe [0-9]+.*@bugs.debian.org</screen>

<para>
as it's often sufficient to just give a portion of the list's e-mail
address.
</para>

<para>
Specify as much of the address as you need to remove ambiguity.  For
example, if you've subscribed to the Mutt mailing list, you will receive
mail addressed to <literal>mutt-users@mutt.org</literal>.  So, to tell
Mutt that this is a mailing list, you could add <literal>lists
mutt-users@</literal> to your initialization file.  To tell Mutt that
you are subscribed to it, add <literal><command>subscribe</command>
mutt-users</literal> to your initialization file instead.  If you also
happen to get mail from someone whose address is
<literal>mutt-users@example.com</literal>, you could use
<literal><command>lists</command> ^mutt-users@mutt\\.org$</literal> or
<literal><command>subscribe</command> ^mutt-users@mutt\\.org$</literal>
to match only mail from the actual list.
</para>

<para>
The <literal>-group</literal> flag adds all of the subsequent regular
expressions to the named <link linkend="addrgroup">address group</link>
in addition to adding to the specified address list.
</para>

<para>
The <quote>unlists</quote> command is used to remove a token from the
list of known and subscribed mailing-lists. Use <quote>unlists *</quote>
to remove all tokens.
</para>

<para>
To remove a mailing list from the list of subscribed mailing lists, but
keep it on the list of known mailing lists, use
<command>unsubscribe</command>.
</para>

</sect1>

<sect1 id="mbox-hook">
<title>Using Multiple Spool Mailboxes</title>

<para>Usage:</para>

<cmdsynopsis>
<command>mbox-hook</command>
<arg choice="plain">
<replaceable class="parameter">[!]regexp</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">mailbox</replaceable>
</arg>
</cmdsynopsis>

<para>
This command is used to move read messages from a specified mailbox to a
different mailbox automatically when you quit or change folders.
<emphasis>regexp</emphasis> is a regular expression specifying the
mailbox to treat as a <quote>spool</quote> mailbox and
<emphasis>mailbox</emphasis> specifies where mail should be saved when
read.
</para>

<para>
The regexp parameter has <link linkend="shortcuts">mailbox
shortcut</link> expansion performed on the first character.
See  <xref linkend="mailbox-hook"/> for more details.
</para>

<para>
Note that execution of mbox-hooks is dependent on the <link
linkend="move">$move</link> configuration variable.  If set to
<quote>no</quote> (the default), mbox-hooks will not be executed.
</para>

<para>
Unlike some of the other <emphasis>hook</emphasis> commands, only the
<emphasis>first</emphasis> matching regexp is used (it is not possible
to save read mail in more than a single mailbox).
</para>

</sect1>

<sect1 id="mailboxes">
<title>Monitoring Incoming Mail</title>

<para>Usage:</para>

<cmdsynopsis>
<command>mailboxes</command>
<arg choice="opt">
  <group choice="opt">
    <arg choice="plain">
      <option>-poll</option>
    </arg>
    <arg choice="plain">
      <option>-nopoll</option>
    </arg>
  </group>
  <group choice="opt">
    <arg choice="plain">
      <option>-label</option>
      <replaceable>label</replaceable>
    </arg>
    <arg choice="plain">
      <option>-nolabel</option>
    </arg>
  </group>
  <arg choice="plain">
    <replaceable class="parameter">mailbox</replaceable>
  </arg>
</arg>
<arg choice="opt" rep="repeat"></arg>

<command>unmailboxes</command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">mailbox</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
This command specifies folders which can receive mail and which will be
checked for new messages periodically.
</para>

<para>
To disable polling, specify <literal>-nopoll</literal> before the
mailbox name.  The <literal>-poll</literal> argument can be used to
reenable polling for an existing mailbox.  If unspecified: a new
mailbox will poll by default, while an existing mailbox will be
unchanged.
</para>

<para>
The <literal>-label</literal> argument can be used to specify an
alternative label to print in the sidebar or mailbox browser instead
of the mailbox path.  A label may be removed via the
<literal>-nolabel</literal> argument.  If unspecified, an existing
mailbox label will be unchanged.
</para>

<para>
<emphasis>mailbox</emphasis> can either be a local file or directory
(Mbox/Mmdf or Maildir/Mh). If Mutt was built with POP and/or IMAP
support, <emphasis>mailbox</emphasis> can also be a POP/IMAP folder
URL. The URL syntax is described in <xref linkend="url-syntax"/>, POP
and IMAP are described in <xref linkend="pop"/> and <xref
linkend="imap"/> respectively.
</para>

<para>
Mutt provides a number of advanced features for handling (possibly many)
folders and new mail within them, please refer to <xref
linkend="new-mail"/> for details (including in what situations and how
often Mutt checks for new mail).
Additionally, <link linkend="new-mail-command">$new_mail_command</link>
can be used to run a command when new mail is detected.
</para>

<para>
The <quote>unmailboxes</quote> command is used to remove a token from
the list of folders which receive mail. Use <quote>unmailboxes *</quote>
to remove all tokens.
</para>

<note>
<para>
The folders in the <command>mailboxes</command> command are resolved
when the command is executed, so if these names contain <link
linkend="shortcuts">shortcut characters</link> (such as <quote>=</quote>
and <quote>!</quote>), any variable definition that affects these
characters (like <link linkend="folder">$folder</link> and <link
linkend="spoolfile">$spoolfile</link>) should be set before the
<command>mailboxes</command> command. If none of these shortcuts are
used, a local path should be absolute as otherwise Mutt tries to find it
relative to the directory from where Mutt was started which may not
always be desired.
</para>
</note>

</sect1>

<sect1 id="my-hdr">
<title>User-Defined Headers</title>

<para>Usage:</para>

<cmdsynopsis>
<command>my_hdr</command>
<arg choice="plain">
<replaceable class="parameter">string</replaceable>
</arg>

<command>unmy_hdr</command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">field</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
The <command>my_hdr</command> command allows you to create your own
header fields which will be added to every message you send and appear
in the editor if <link linkend="edit-headers">$edit_headers</link> is
set.
</para>

<para>
For example, if you would like to add an <quote>Organization:</quote>
header field to all of your outgoing messages, you can put the command
something like shown in <xref linkend="ex-my-hdr"/> in your
<literal>.muttrc</literal>.
</para>

<example id="ex-my-hdr">
<title>Defining custom headers</title>
<screen>
my_hdr Organization: A Really Big Company, Anytown, USA
</screen>
</example>

<note>
<para>
Space characters are <emphasis>not</emphasis> allowed between the
keyword and the colon (<quote>:</quote>). The standard for electronic
mail (RFC2822) says that space is illegal there, so Mutt enforces the
rule.
</para>
</note>

<para>
If you would like to add a header field to a single message, you should
either set the <link linkend="edit-headers">$edit_headers</link>
variable, or use the <literal>&lt;edit-headers&gt;</literal> function
(default: <quote>E</quote>) in the compose menu so that you can edit the
header of your message along with the body.
</para>

<para>
To remove user defined header fields, use the
<command>unmy_hdr</command> command. You may specify an asterisk
(<quote>*</quote>) to remove all header fields, or the fields to
remove. For example, to remove all <quote>To</quote> and
<quote>Cc</quote> header fields, you could use:
</para>

<screen>
unmy_hdr to cc
</screen>

</sect1>

<sect1 id="save-hook">
<title>Specify Default Save Mailbox</title>

<para>Usage:</para>

<cmdsynopsis>
<command>save-hook</command>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">mailbox</replaceable>
</arg>
</cmdsynopsis>

<para>
This command is used to override the default mailbox used when saving
messages. <emphasis>mailbox</emphasis> will be used as the default if
the message matches <emphasis>pattern</emphasis>, see <xref
linkend="pattern-hook"/> for information on the exact format.
</para>

<para>
To provide more flexibility and good defaults, Mutt applies the expandos
of <link linkend="index-format">$index_format</link> to
<emphasis>mailbox</emphasis> after it was expanded.
</para>

<example id="ex-save-hook-exando">
<title>Using %-expandos in <command>save-hook</command></title>
<screen>
<emphasis role="comment"># default: save all to ~/Mail/&lt;author name&gt;</emphasis>
save-hook . ~/Mail/%F

<emphasis role="comment"># save from me@turing.cs.hmc.edu and me@cs.hmc.edu to $folder/elkins</emphasis>
save-hook me@(turing\\.)?cs\\.hmc\\.edu$ +elkins

<emphasis role="comment"># save from aol.com to $folder/spam</emphasis>
save-hook aol\\.com$ +spam
</screen>
</example>

<para>
Also see the <link
linkend="fcc-save-hook"><command>fcc-save-hook</command></link> command.
</para>

</sect1>

<sect1 id="fcc-hook">
<title>Specify Default Fcc: Mailbox When Composing</title>

<para>Usage:</para>

<cmdsynopsis>
<command>fcc-hook</command>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">mailbox</replaceable>
</arg>
</cmdsynopsis>

<para>
This command is used to save outgoing mail in a mailbox other than <link
linkend="record">$record</link>.  Mutt searches the initial list of
message recipients for the first matching <emphasis>pattern</emphasis>
and uses <emphasis>mailbox</emphasis> as the default Fcc: mailbox.  If
no match is found the message will be saved to <link
linkend="record">$record</link> mailbox.
</para>

<para>
To provide more flexibility and good defaults, Mutt applies the
expandos of <link linkend="index-format">$index_format</link> to
<emphasis>mailbox</emphasis> after it was expanded.
</para>

<para>
See <xref linkend="pattern-hook"/> for information on the exact format
of <emphasis>pattern</emphasis>.
</para>

<screen>fcc-hook [@.]aol\\.com$ +spammers</screen>

<para>
...will save a copy of all messages going to the aol.com domain to the
`+spammers' mailbox by default.  Also see the <link
linkend="fcc-save-hook"><command>fcc-save-hook</command></link> command.
</para>

<para>
Multiple mailboxes may be specified by separating them with <link
linkend="fcc-delimiter">$fcc_delimiter</link>, if set:
</para>

<screen>
  set fcc_delimiter = ','
  fcc-hook 'foo@example\.com$' '+one,+two'
</screen>

</sect1>

<sect1 id="fcc-save-hook">
<title>Specify Default Save Filename and Default Fcc: Mailbox at Once</title>

<para>Usage:</para>

<cmdsynopsis>
<command>fcc-save-hook</command>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">mailbox</replaceable>
</arg>
</cmdsynopsis>

<para>
This command is a shortcut, almost equivalent to doing both a <link
linkend="fcc-hook"><command>fcc-hook</command></link> and a <link
linkend="save-hook"><command>save-hook</command></link> with its
arguments, including %-expansion on <emphasis>mailbox</emphasis>
according to <link linkend="index-format">$index_format</link>.
</para>

<para>
Note, however that the fcc-save-hook is not designed to take advantage
of multiple mailboxes, as fcc-hook is.  For correct behavior, you should
use separate fcc and save hooks in that case.
</para>

</sect1>

<sect1 id="send-hook">
<title>Change Settings Based Upon Message Recipients</title>

<anchor id="reply-hook"/>
<anchor id="send2-hook"/>

<para>Usage:</para>

<cmdsynopsis>
<command>reply-hook</command>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">command</replaceable>
</arg>

<command>send-hook</command>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">command</replaceable>
</arg>

<command>send2-hook</command>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">command</replaceable>
</arg>
</cmdsynopsis>

<para>
These commands can be used to execute arbitrary configuration commands
based upon recipients of the message.  <emphasis>pattern</emphasis> is
used to match the message, see <xref linkend="pattern-hook"/> for
details. <emphasis>command</emphasis> is executed when
<emphasis>pattern</emphasis> matches.
</para>

<para>
<command>reply-hook</command> is matched against the message you are
<emphasis>replying to</emphasis>, instead of the message you are
<emphasis>sending</emphasis>.  <command>send-hook</command> is matched
against all messages, both <emphasis>new</emphasis> and
<emphasis>replies</emphasis>.
</para>

<note>
<para>
<command>reply-hook</command>s are matched <emphasis>before</emphasis> the
<command>send-hook</command>, <emphasis>regardless</emphasis> of the order
specified in the user's configuration file.  However, you can inhibit
<command>send-hook</command> in the reply case by using the pattern
<literal>'! ~Q'</literal> (<emphasis>not replied</emphasis>, see
<xref linkend="pattern-hook"/>) in the <command>send-hook</command> to tell
when <command>reply-hook</command> have been executed.
</para>
</note>

<para>
<command>send2-hook</command> is matched every time a message is
changed, either by editing it, or by using the compose menu to change
its recipients or subject.  <command>send2-hook</command> is executed
after <command>send-hook</command>, and can, e.g., be used to set
parameters such as the <link linkend="sendmail">$sendmail</link>
variable depending on the message's sender address.
</para>

<para>
For each type of <command>send-hook</command> or
<command>reply-hook</command>, when multiple matches occur, commands are
executed in the order they are specified in the
<literal>.muttrc</literal> (for that type of hook).
</para>

<para>
Example: <literal><command>send-hook</command> mutt
"<command>set</command> mime_forward signature=''"</literal>
</para>

<para>
Another typical use for this command is to change the values of the
<link linkend="attribution">$attribution</link>, <link
linkend="attribution-locale">$attribution_locale</link>, and <link
linkend="signature">$signature</link> variables in order to change the
language of the attributions and signatures based upon the recipients.
</para>

<note>
<para>
<command>send-hook</command>'s are only executed once after getting the
initial list of recipients.  They are not executed when resuming a postponed
draft.  Adding a recipient after replying or
editing the message will not cause any <command>send-hook</command> to
be executed, similarly if <link linkend="autoedit">$autoedit</link> is
set (as then the initial list of recipients is empty). Also note that
<link linkend="my-hdr"><command>my_hdr</command></link> commands which
modify recipient headers, or the message's subject, don't have any
effect on the current message when executed from a
<command>send-hook</command>.
</para>
</note>

</sect1>

<sect1 id="message-hook">
<title>Change Settings Before Formatting a Message</title>

<para>Usage:</para>

<cmdsynopsis>
<command>message-hook</command>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">command</replaceable>
</arg>
</cmdsynopsis>

<para>
This command can be used to execute arbitrary configuration commands
before viewing or formatting a message based upon information about the
message.  <emphasis>command</emphasis> is executed if the
<emphasis>pattern</emphasis> matches the message to be displayed. When
multiple matches occur, commands are executed in the order they are
specified in the <literal>.muttrc</literal>.
</para>

<para>
See <xref linkend="pattern-hook"/> for information on the exact format
of <emphasis>pattern</emphasis>.
</para>

<para>
Example:
</para>

<screen>
message-hook ~A 'set pager=builtin'
message-hook '~f freshmeat-news' 'set pager="less \"+/^  subject: .*\""'
</screen>

</sect1>

<sect1 id="crypt-hook">
<title>Choosing the Cryptographic Key of the Recipient</title>

<para>Usage:</para>

<cmdsynopsis>
<command>crypt-hook</command>
<arg choice="plain">
<replaceable class="parameter">regexp</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">keyid</replaceable>
</arg>
</cmdsynopsis>

<para>
When encrypting messages with PGP/GnuPG or OpenSSL, you may want to
associate a certain key with a given e-mail address automatically,
either because the recipient's public key can't be deduced from the
destination address, or because, for some reasons, you need to override
the key Mutt would normally use.  The <command>crypt-hook</command>
command provides a method by which you can specify the ID of the public
key to be used when encrypting messages to a certain recipient.
You may use multiple crypt-hooks with the same regexp; multiple
matching crypt-hooks result in the use of multiple keyids for
a recipient.  During key selection, Mutt will confirm whether each
crypt-hook is to be used (unless the <link
linkend="crypt-confirmhook">$crypt_confirmhook</link> option is unset).
If all crypt-hooks for a recipient are declined, Mutt will use the
original recipient address for key selection instead.
</para>

<para>
The meaning of <emphasis>keyid</emphasis> is to be taken broadly in this
context: You can either put a numerical key ID or fingerprint here, an
e-mail address, or even just a real name.
</para>

</sect1>

<sect1 id="index-format-hook">
<title>Dynamically Changing $index_format using Patterns</title>

<para>Usage:</para>

<cmdsynopsis>
<command>index-format-hook</command>
<arg choice="plain">
<replaceable class="parameter">name</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">format-string</replaceable>
</arg>
</cmdsynopsis>

<para>
This command is used to inject format strings dynamically into <link
linkend="index-format">$index_format</link> based on pattern matching
against the current message.
</para>

<para>
The <link linkend="index-format">$index_format</link> expando
<emphasis>%@name@</emphasis> specifies a placeholder for the
injection.  Index-format-hooks with the same <emphasis>name</emphasis>
are matched using <link
linkend="patterns"><emphasis>pattern</emphasis></link> against the
current message.  Matching is done in the order specified in the
.muttrc, with the first match being used.  The hook's
<emphasis>format-string</emphasis> is then substituted and evaluated.
</para>

<para>
Because the first match is used, best practice is to put a catch-all
<emphasis>~A</emphasis> pattern as the last hook.  Here is an example
showing how to implement dynamic date formatting:
</para>

<screen>
set index_format="%4C %-6@date@ %-15.15F %Z (%4c) %s"

index-format-hook  date  "~d&lt;1d"    "%[%H:%M]"
index-format-hook  date  "~d&lt;1m"    "%[%a %d]"
index-format-hook  date  "~d&lt;1y"    "%[%b %d]"
index-format-hook  date  "~A"       "%[%m/%y]"
</screen>

<para>
Another example, showing a way to prepend to the subject.  Note that
without a catch-all ~A pattern, no match results in the expando
being replaced with an empty string.
</para>

<screen>
set index_format="%4C %@subj_flags@%s"

index-format-hook  subj_flags  "~f boss@example.com"    "** BOSS ** "
index-format-hook  subj_flags  "~f spouse@example.com"  ":-) "
</screen>
</sect1>

<sect1 id="push">
<title>Adding Key Sequences to the Keyboard Buffer</title>

<para>Usage:</para>

<cmdsynopsis>
<command>push</command>
<arg choice="plain">
<replaceable class="parameter">string</replaceable>
</arg>
</cmdsynopsis>

<para>
This command adds the named string to the beginning of the keyboard buffer. The string
may contain control characters, key names and function names like the
sequence string in the <link linkend="macro">macro</link> command. You
may use it to automatically run a sequence of commands at startup, or
when entering certain folders. For example, <xref
linkend="ex-folder-hook-push"/> shows how to automatically collapse all
threads when entering a folder.
</para>

<example id="ex-folder-hook-push">
<title>Embedding <command>push</command> in <command>folder-hook</command></title>
<screen>
folder-hook . 'push &lt;collapse-all&gt;'
</screen>
</example>

<para>
For using functions like shown in the example, it's important to use
angle brackets (<quote>&lt;</quote> and <quote>&gt;</quote>) to make
Mutt recognize the input as a function name. Otherwise it will simulate
individual just keystrokes, i.e. <quote><literal>push
collapse-all</literal></quote> would be interpreted as if you had typed
<quote>c</quote>, followed by <quote>o</quote>, followed by
<quote>l</quote>, ..., which is not desired and may lead to very
unexpected behavior.
</para>

<para>
Keystrokes can be used, too, but are less portable because of
potentially changed key bindings. With default bindings, this is
equivalent to the above example:
</para>

<screen>
folder-hook . 'push \eV'
</screen>

<para>
because it simulates that Esc+V was pressed (which is the default
binding of <literal>&lt;collapse-all&gt;</literal>).
</para>

</sect1>

<sect1 id="exec">
<title>Executing Functions</title>

<para>Usage:</para>

<cmdsynopsis>
<command>exec</command>
<arg choice="plain">
<replaceable class="parameter">function</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">function</replaceable>
</arg>
</cmdsynopsis>

<para>
This command can be used to execute any function. Functions are listed
in the <link linkend="functions">function reference</link>.
<quote><command>exec</command> <literal>function</literal></quote> is
equivalent to <quote><literal>push &lt;function&gt;</literal></quote>.
</para>

</sect1>

<sect1 id="score-command">
<title>Message Scoring</title>

<para>Usage:</para>

<cmdsynopsis>
<command>score</command>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">value</replaceable>
</arg>

<command>unscore</command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">pattern</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
The <command>score</command> commands adds <emphasis>value</emphasis>
to a message's score if <emphasis>pattern</emphasis> matches it.
<emphasis>pattern</emphasis> is a string in the format described in
the <link linkend="patterns">patterns</link> section (note: For
efficiency reasons, patterns which scan information not available in
the index, such as <literal>~b</literal>, <literal>~B</literal>,
<literal>~h</literal>, <literal>~M</literal>, or <literal>~X</literal>
may not be used).  <emphasis>value</emphasis> is a positive or
negative integer.  A message's final score is the sum total of all
matching <command>score</command> entries.  However, you may
optionally prefix <emphasis>value</emphasis> with an equal sign
(<quote>=</quote>) to cause evaluation to stop at a particular entry
if there is a match.  Negative final scores are rounded up to 0.
</para>

<para>
The <command>unscore</command> command removes score entries from the
list.  You <emphasis>must</emphasis> specify the same pattern specified
in the <command>score</command> command for it to be removed.  The
pattern <quote>*</quote> is a special token which means to clear the
list of all score entries.
</para>

<para>
Scoring occurs as the messages are read in, before the mailbox is
sorted.  Because of this, patterns which depend on threading, such as
<emphasis>~=</emphasis>, <emphasis>~$</emphasis>, and
<emphasis>~()</emphasis>, will not work by default.  A workaround is
to push the scoring command in a folder hook.  This will cause the
mailbox to be rescored after it is opened and input starts being
processed:
</para>

<screen>
folder-hook . 'push "&lt;enter-command&gt;score ~= 10&lt;enter&gt;"'
</screen>

</sect1>

<sect1 id="spam">
<title>Spam Detection</title>

<para>Usage:</para>

<cmdsynopsis>
<command>spam</command>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">format</replaceable>
</arg>

<command>nospam</command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
Mutt has generalized support for external spam-scoring filters.  By
defining your spam patterns with the <command>spam</command> and
<literal>nospam</literal> commands, you can <emphasis>limit</emphasis>,
<emphasis>search</emphasis>, and <emphasis>sort</emphasis> your mail
based on its spam attributes, as determined by the external filter. You
also can display the spam attributes in your index display using the
<literal>%H</literal> selector in the <link
linkend="index-format">$index_format</link> variable. (Tip: try
<literal>%?H?[%H] ?</literal> to display spam tags only when they are
defined for a given message.)
</para>

<para>
Note: the value displayed by <literal>%H</literal> and searched by
<literal>~H</literal> is stored in the <link linkend="caching">header
cache</link>.  Mutt isn't smart enough to invalidate a header cache
entry based on changing <literal>spam</literal> rules, so if you
aren't seeing correct <literal>%H</literal> values, try temporarily
turning off the header cache.  If that fixes the problem, then once
your spam rules are set to your liking, remove your stale header cache
files and turn the header cache back on.
</para>

<para>
Your first step is to define your external filter's spam patterns using
the <command>spam</command> command. <emphasis>pattern</emphasis> should
be a regular expression that matches a header in a mail message. If any
message in the mailbox matches this regular expression, it will receive
a <quote>spam tag</quote> or <quote>spam attribute</quote> (unless it
also matches a <command>nospam</command> pattern &mdash; see below.) The
appearance of this attribute is entirely up to you, and is governed by
the <emphasis>format</emphasis> parameter. <emphasis>format</emphasis>
can be any static text, but it also can include back-references from the
<emphasis>pattern</emphasis> expression. (A regular expression
<quote>back-reference</quote> refers to a sub-expression contained
within parentheses.) <literal>%1</literal> is replaced with the first
back-reference in the regex, <literal>%2</literal> with the second, etc.
</para>

<para>
To match spam tags, mutt needs the corresponding header information
which is always the case for local and POP folders but not for IMAP in
the default configuration. Depending on the spam header to be analyzed,
<link linkend="imap-headers">$imap_headers</link> may need to be
adjusted.
</para>

<para>
If you're using multiple spam filters, a message can have more than one
spam-related header. You can define <command>spam</command> patterns for
each filter you use. If a message matches two or more of these patterns,
and the <link linkend="spam-separator">$spam_separator</link> variable
is set to a string, then the message's spam tag will consist of all the
<emphasis>format</emphasis> strings joined together, with the value of
<link linkend="spam-separator">$spam_separator</link> separating them.
</para>

<para>
For example, suppose one uses DCC, SpamAssassin, and PureMessage, then
the configuration might look like in <xref linkend="ex-spam"/>.
</para>

<example id="ex-spam">
<title>Configuring spam detection</title>
<screen>
spam "X-DCC-.*-Metrics:.*(....)=many"         "90+/DCC-%1"
spam "X-Spam-Status: Yes"                     "90+/SA"
spam "X-PerlMX-Spam: .*Probability=([0-9]+)%" "%1/PM"
set spam_separator=", "
</screen>
</example>

<para>
If then a message is received that DCC registered with
<quote>many</quote> hits under the <quote>Fuz2</quote> checksum, and
that PureMessage registered with a 97% probability of being spam, that
message's spam tag would read <literal>90+/DCC-Fuz2,
97/PM</literal>. (The four characters before <quote>=many</quote> in a
DCC report indicate the checksum used &mdash; in this case,
<quote>Fuz2</quote>.)
</para>

<para>
If the <link linkend="spam-separator">$spam_separator</link> variable is
unset, then each spam pattern match supersedes the previous one. Instead
of getting joined <emphasis>format</emphasis> strings, you'll get only
the last one to match.
</para>

<para>
The spam tag is what will be displayed in the index when you use
<literal>%H</literal> in the <link
linkend="index-format">$index_format</link> variable. It's also the
string that the <literal>~H</literal> pattern-matching expression
matches against for <literal>&lt;search&gt;</literal> and
<literal>&lt;limit&gt;</literal> functions. And it's what sorting by
spam attribute will use as a sort key.
</para>

<para>
That's a pretty complicated example, and most people's actual
environments will have only one spam filter. The simpler your
configuration, the more effective Mutt can be, especially when it comes
to sorting.
</para>

<para>
Generally, when you sort by spam tag, Mutt will sort
<emphasis>lexically</emphasis> &mdash; that is, by ordering strings
alphanumerically. However, if a spam tag begins with a number, Mutt will
sort numerically first, and lexically only when two numbers are equal in
value. (This is like UNIX's <literal>sort -n</literal>.) A message with
no spam attributes at all &mdash; that is, one that didn't match
<emphasis>any</emphasis> of your <command>spam</command> patterns
&mdash; is sorted at lowest priority. Numbers are sorted next, beginning
with 0 and ranging upward. Finally, non-numeric strings are sorted, with
<quote>a</quote> taking lower priority than <quote>z</quote>. Clearly,
in general, sorting by spam tags is most effective when you can coerce
your filter to give you a raw number. But in case you can't, Mutt can
still do something useful.
</para>

<para>
The <command>nospam</command> command can be used to write exceptions to
<command>spam</command> patterns. If a header pattern matches something
in a <command>spam</command> command, but you nonetheless do not want it
to receive a spam tag, you can list a more precise pattern under a
<command>nospam</command> command.
</para>

<para>
If the <emphasis>pattern</emphasis> given to <command>nospam</command>
is exactly the same as the <emphasis>pattern</emphasis> on an existing
<command>spam</command> list entry, the effect will be to remove the
entry from the spam list, instead of adding an exception.  Likewise, if
the <emphasis>pattern</emphasis> for a <command>spam</command> command
matches an entry on the <command>nospam</command> list, that nospam
entry will be removed. If the <emphasis>pattern</emphasis> for
<command>nospam</command> is <quote>*</quote>, <emphasis>all entries on
both lists</emphasis> will be removed. This might be the default action
if you use <command>spam</command> and <command>nospam</command> in
conjunction with a <command>folder-hook</command>.
</para>

<para>
You can have as many <command>spam</command> or
<command>nospam</command> commands as you like.  You can even do your
own primitive <command>spam</command> detection within Mutt &mdash; for
example, if you consider all mail from <literal>MAILER-DAEMON</literal>
to be spam, you can use a <command>spam</command> command like this:
</para>

<screen>
spam "^From: .*MAILER-DAEMON"       "999"
</screen>

</sect1>

<sect1 id="set">
<title>Setting and Querying Variables</title>

<sect2 id="var-types">
<title>Variable Types</title>

<para>
Mutt supports these types of configuration variables:
</para>

<variablelist>
<varlistentry>
<term>boolean</term>
<listitem>
<para>
A boolean expression, either <quote>yes</quote> or <quote>no</quote>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>number</term>
<listitem>
<para>
A signed integer number in the range -32768 to 32767.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>number (long)</term>
<listitem>
<para>
A signed integer number in the range -2147483648 to 2147483647.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>string</term>
<listitem>
<para>
Arbitrary text.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>path</term>
<listitem>
<para>
A specialized string for representing paths including support for
mailbox shortcuts (see <xref linkend="shortcuts"/>) as well as tilde
(<quote>~</quote>) for a user's home directory and more.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>quadoption</term>
<listitem>
<para>
Like a boolean but triggers a prompt when set to <quote>ask-yes</quote>
or <quote>ask-no</quote> with <quote>yes</quote> and <quote>no</quote>
preselected respectively.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>sort order</term>
<listitem>
<para>
A specialized string allowing only particular words as values depending
on the variable.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>regular expression</term>
<listitem>
<para>
A regular expression, see <xref linkend="regexp"/> for an introduction.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>folder magic</term>
<listitem>
<para>
Specifies the type of folder to use: <emphasis>mbox</emphasis>,
<emphasis>mmdf</emphasis>, <emphasis>mh</emphasis> or
<emphasis>maildir</emphasis>.  Currently only used to determine the type
for newly created folders.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>e-mail address</term>
<listitem>
<para>
An e-mail address either with or without realname. The older
<quote><literal>user@example.org (Joe User)</literal></quote> form is
supported but strongly deprecated.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>user-defined</term>
<listitem>
<para>
Arbitrary text, see <xref linkend="set-myvar"/> for details.
</para>
</listitem>
</varlistentry>
</variablelist>

</sect2>

<sect2 id="set-commands">
<title>Commands</title>

<para>
The following commands are available to manipulate and query variables:
</para>

<para>Usage:</para>

<cmdsynopsis>
<command>set</command>
<group choice="req">
<arg choice="plain">
<group choice="opt">
<arg choice="plain"><option>no</option></arg>
<arg choice="plain"><option>inv</option></arg>
</group>
<replaceable class="parameter">variable</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">variable=value</replaceable>
</arg>
</group>
<arg choice="opt" rep="repeat"></arg>

<command>toggle</command>
<arg choice="plain">
<replaceable class="parameter">variable</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">variable</replaceable>
</arg>

<command>unset</command>
<arg choice="plain">
<replaceable class="parameter">variable</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">variable</replaceable>
</arg>

<command>reset</command>
<arg choice="plain">
<replaceable class="parameter">variable</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">variable</replaceable>
</arg>
</cmdsynopsis>

<para>
This command is used to set (and unset) <link
linkend="variables">configuration variables</link>.  There are four
basic types of variables: boolean, number, string and quadoption.
<emphasis>boolean</emphasis> variables can be <emphasis>set</emphasis>
(true) or <emphasis>unset</emphasis> (false).
<emphasis>number</emphasis> variables can be assigned a positive integer
value.  <emphasis>string</emphasis> variables consist of any number of
printable characters and must be enclosed in quotes if they contain
spaces or tabs.  You may also use the escape sequences <quote>\n</quote>
and <quote>\t</quote> for newline and tab, respectively.
<emphasis>quadoption</emphasis> variables are used to control whether or
not to be prompted for certain actions, or to specify a default action.
A value of <emphasis>yes</emphasis> will cause the action to be carried
out automatically as if you had answered yes to the question.
Similarly, a value of <emphasis>no</emphasis> will cause the action to
be carried out as if you had answered <quote>no.</quote> A value of
<emphasis>ask-yes</emphasis> will cause a prompt with a default answer
of <quote>yes</quote> and <emphasis>ask-no</emphasis> will provide a
default answer of <quote>no.</quote>
</para>

<para>
Prefixing a variable with <quote>no</quote> will unset it.  Example:
<literal><command>set</command> noaskbcc</literal>.
</para>

<para>
For <emphasis>boolean</emphasis> variables, you may optionally prefix
the variable name with <literal>inv</literal> to toggle the value (on or
off).  This is useful when writing macros.  Example:
<literal><command>set</command> invsmart_wrap</literal>.
</para>

<para>
The <command>toggle</command> command automatically prepends the
<literal>inv</literal> prefix to all specified variables.
</para>

<para>
The <command>unset</command> command automatically prepends the
<literal>no</literal> prefix to all specified variables.
</para>

<para>
Using the <literal>&lt;enter-command&gt;</literal> function in the
<emphasis>index</emphasis> menu, you can query the value of a variable
by prefixing the name of the variable with a question mark:
</para>

<screen>
set ?allow_8bit
</screen>

<para>
The question mark is actually only required for boolean and quadoption
variables.
</para>

<para>
The <command>reset</command> command resets all given variables to the
compile time defaults (hopefully mentioned in this manual). If you use
the command <command>set</command> and prefix the variable with
<quote>&amp;</quote> this has the same behavior as the
<command>reset</command> command.
</para>

<para>
With the <command>reset</command> command there exists the special
variable <quote>all</quote>, which allows you to reset all variables to
their system defaults.
</para>

</sect2>

<sect2 id="set-myvar">
<title>User-Defined Variables</title>

<sect3 id="set-myvar-intro">
<title>Introduction</title>

<para>
Along with the variables listed in the <link
linkend="variables">Configuration variables</link> section, Mutt
supports user-defined variables with names starting with
<literal>my_</literal> as in, for example, <literal>my_cfgdir</literal>.
</para>

<para>
The <command>set</command> command either creates a custom
<literal>my_</literal> variable or changes its value if it does exist
already. The <command>unset</command> and <command>reset</command>
commands remove the variable entirely.
</para>

<para>
Since user-defined variables are expanded in the same way that
environment variables are (except for the <link
linkend="shell-escape">shell-escape</link> command and backtick
expansion), this feature can be used to make configuration files more
readable.
</para>

</sect3>

<sect3 id="set-myvar-examples">
<title>Examples</title>

<para>
The following example defines and uses the variable
<literal>my_cfgdir</literal> to abbreviate the calls of the <link
linkend="source"><command>source</command></link> command:
</para>

<example id="ex-myvar1">
<title>Using user-defined variables for config file readability</title>
<screen>
set my_cfgdir = $HOME/mutt/config

source $my_cfgdir/hooks
source $my_cfgdir/macros
<emphasis role="comment"># more source commands...</emphasis>
</screen>
</example>

<para>
A custom variable can also be used in macros to backup the current value
of another variable. In the following example, the value of the <link
linkend="delete">$delete</link> is changed temporarily while its
original value is saved as <literal>my_delete</literal>.  After the
macro has executed all commands, the original value of <link
linkend="delete">$delete</link> is restored.
</para>

<example id="ex-myvar2">
<title>Using user-defined variables for backing up other config option values</title>
<screen>
macro pager ,x '\
&lt;enter-command&gt;set my_delete=$delete&lt;enter&gt;\
&lt;enter-command&gt;set delete=yes&lt;enter&gt;\
...\
&lt;enter-command&gt;set delete=$my_delete&lt;enter&gt;'
</screen>
</example>

<para>
Since Mutt expands such values already when parsing the configuration
file(s), the value of <literal>$my_delete</literal> in the
last example would be the value of <link linkend="delete">$delete</link> exactly
as it was at that point during parsing the configuration file. If
another statement would change the value for <link linkend="delete">$delete</link>
later in the same or another file, it would have no effect on
<literal>$my_delete</literal>. However, the expansion can
be deferred to runtime, as shown in the next example, when escaping the
dollar sign.
</para>

<example id="ex-myvar3">
<title>Deferring user-defined variable expansion to runtime</title>
<screen>
macro pager &lt;PageDown&gt; "\
&lt;enter-command&gt; set my_old_pager_stop=\$pager_stop pager_stop&lt;Enter&gt;\
&lt;next-page&gt;\
&lt;enter-command&gt; set pager_stop=\$my_old_pager_stop&lt;Enter&gt;\
&lt;enter-command&gt; unset my_old_pager_stop&lt;Enter&gt;"
</screen>
</example>

<para>
Note that there is a space between
<literal>&lt;enter-command&gt;</literal> and the <command>set</command>
configuration command, preventing Mutt from recording the
<command>macro</command>'s commands into its history.
</para>

</sect3>

</sect2>

<sect2 id="set-conversions">
<title>Type Conversions</title>

<para>
Variables are always assigned string values which Mutt parses into its
internal representation according to the type of the variable, for
example an integer number for numeric types. For all queries (including
$-expansion) the value is converted from its internal type back into
string. As a result, any variable can be assigned any value given that
its content is valid for the target. This also counts for custom
variables which are of type string. In case of parsing errors, Mutt will
print error messages. <xref linkend="ex-myvar4"/> demonstrates type
conversions.
</para>

<example id="ex-myvar4">
<title>Type conversions using variables</title>
<screen>
set my_lines = "5"                <emphasis role="comment"># value is string "5"</emphasis>
set pager_index_lines = $my_lines <emphasis role="comment"># value is integer 5</emphasis>

set my_sort = "date-received"     <emphasis role="comment"># value is string "date-received"</emphasis>
set sort = "last-$my_sort"        <emphasis role="comment"># value is sort last-date-received</emphasis>

set my_inc = $read_inc            <emphasis role="comment"># value is string "10" (default of $read_inc)</emphasis>
set my_foo = $my_inc              <emphasis role="comment"># value is string "10"</emphasis>
</screen>
</example>

<para>
These assignments are all valid. If, however, the value of
<literal>$my_lines</literal> would have been
<quote>five</quote> (or something else that cannot be parsed into a
number), the assignment to
<literal>$pager_index_lines</literal> would have
produced an error message.
</para>

<para>
Type conversion applies to all configuration commands which take
arguments. But please note that every expanded value of a variable is
considered just a single token. A working example is:
</para>

<screen>
set my_pattern = "~A"
set my_number = "10"

<emphasis role="comment"># same as: score ~A +10</emphasis>
score $my_pattern +$my_number</screen>

<para>
What does <emphasis>not</emphasis> work is:
</para>

<screen>
set my_mx = "+mailbox1 +mailbox2"
mailboxes $my_mx +mailbox3</screen>

<para>
because the value of <literal>$my_mx</literal> is interpreted as a
single mailbox named <quote>+mailbox1 +mailbox2</quote> and not two
distinct mailboxes.
</para>

</sect2>

</sect1>

<sect1 id="source">
<title>Reading Initialization Commands From Another File</title>

<para>Usage:</para>

<cmdsynopsis>
<command>source</command>
<arg choice="plain">
<replaceable class="parameter">filename</replaceable>
</arg>
</cmdsynopsis>

<para>
This command allows the inclusion of initialization commands from other
files.  For example, I place all of my aliases in
<literal>~/.mail_aliases</literal> so that I can make my
<literal>~/.muttrc</literal> readable and keep my aliases private.
</para>

<para>
If the filename begins with a tilde (<quote>~</quote>), it will be
expanded to the path of your home directory.
</para>

<para>
If the filename ends with a vertical bar (<quote>|</quote>), then
<emphasis>filename</emphasis> is considered to be an executable program
from which to read input (e.g.  <literal><command>source</command>
~/bin/myscript|</literal>).
</para>

</sect1>

<sect1 id="unhook">
<title>Removing Hooks</title>

<para>Usage:</para>

<cmdsynopsis>
<command>unhook</command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">hook-type</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
This command permits you to flush hooks you have previously defined.
You can either remove all hooks by giving the <quote>*</quote> character
as an argument, or you can remove all hooks of a specific type by saying
something like <literal><command>unhook</command> send-hook</literal>.
</para>

</sect1>

<sect1 id="formatstrings">
<title>Format Strings</title>

<sect2 id="formatstrings-basics">
<title>Basic usage</title>

<para>
Format strings are a general concept you'll find in several locations
through the Mutt configuration, especially in the <link
linkend="index-format">$index_format</link>, <link
linkend="pager-format">$pager_format</link>, <link
linkend="status-format">$status_format</link>, and other related
variables. These can be very straightforward, and it's quite possible
you already know how to use them.
</para>

<para>
The most basic format string element is a percent symbol followed by
another character. For example, <literal>%s</literal> represents a
message's Subject: header in the <link
linkend="index-format">$index_format</link> variable. The
<quote>expandos</quote> available are documented with each format
variable, but there are general modifiers available with all formatting
expandos, too. Those are our concern here.
</para>

<para>
Some of the modifiers are borrowed right out of C (though you might know
them from Perl, Python, shell, or another language). These are the
<literal>[-]m.n</literal> modifiers, as in
<literal>%-12.12s</literal>. As with such programming languages, these
modifiers allow you to specify the minimum and maximum size of the
resulting string, as well as its justification. If the <quote>-</quote>
sign follows the percent, the string will be left-justified instead of
right-justified. If there's a number immediately following that, it's
the minimum amount of space the formatted string will occupy &mdash; if
it's naturally smaller than that, it will be padded out with spaces.  If
a decimal point and another number follow, that's the maximum space
allowable &mdash; the string will not be permitted to exceed that width,
no matter its natural size. Each of these three elements is optional, so
that all these are legal format strings: <literal>%-12s</literal>,
<literal>%4c</literal>, <literal>%.15F</literal> and
<literal>%-12.15L</literal>.
</para>

<para>
Mutt adds some other modifiers to format strings. If you use an equals
symbol (<literal>=</literal>) as a numeric prefix (like the minus
above), it will force the string to be centered within its minimum space
range. For example, <literal>%=14y</literal> will reserve 14 characters
for the %y expansion &mdash; that's the X-Label: header, in <link
linkend="index-format">$index_format</link>. If the expansion results in
a string less than 14 characters, it will be centered in a 14-character
space.  If the X-Label for a message were <quote>test</quote>, that
expansion would look like
<quote>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;test&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</quote>.
</para>

<para>
There are two very little-known modifiers that affect the way that an
expando is replaced. If there is an underline (<quote>_</quote>)
character between any format modifiers (as above) and the expando
letter, it will expands in all lower case. And if you use a colon
(<quote>:</quote>), it will replace all decimal points with underlines.
</para>

</sect2>

<sect2 id="formatstrings-conditionals">
<title>Conditionals</title>

<para>
Depending on the format string variable, some of its sequences can be
used to optionally print a string if their value is nonzero. For
example, you may only want to see the number of flagged messages if such
messages exist, since zero is not particularly meaningful. To optionally
print a string based upon one of the above sequences, the following
construct is used:
</para>

<screen>
%?&lt;sequence_char&gt;?&lt;optional_string&gt;?</screen>

<para>
where <emphasis>sequence_char</emphasis> is an expando, and
<emphasis>optional_string</emphasis> is the string you would like
printed if <emphasis>sequence_char</emphasis> is nonzero.
<emphasis>optional_string</emphasis> may contain other sequences as well
as normal text, but you may not nest optional strings.
</para>

<para>
Here is an example illustrating how to optionally print the number of
new messages in a mailbox in <link
linkend="status-format">$status_format</link>:
</para>

<screen>
%?n?%n new messages.?</screen>

<para>
You can also switch between two strings using the following construct:
</para>

<screen>
%?&lt;sequence_char&gt;?&lt;if_string&gt;&amp;&lt;else_string&gt;?</screen>

<para>
If the value of <emphasis>sequence_char</emphasis> is non-zero,
<emphasis>if_string</emphasis> will be expanded, otherwise
<emphasis>else_string</emphasis> will be expanded.
</para>

</sect2>

<sect2 id="formatstrings-filters">
<title>Filters</title>

<para>
Any format string ending in a vertical bar (<quote>|</quote>) will be
expanded and piped through the first word in the string, using spaces as
separator. The string returned will be used for display.  If the
returned string ends in %, it will be passed through the formatter a
second time. This allows the filter to generate a replacement format
string including % expandos.
</para>

<para>
All % expandos in a format string are expanded before the script is
called so that:
</para>

<example id="ex-fmtpipe">
<title>Using external filters in format strings</title>
<screen>
set status_format="script.sh '%r %f (%L)'|"
</screen>
</example>

<para>
will make Mutt expand <literal>%r</literal>, <literal>%f</literal> and
<literal>%L</literal> before calling the script. The example also shows
that arguments can be quoted: the script will receive the expanded
string between the single quotes as the only argument.
</para>

<para>
A practical example is the <literal>mutt_xtitle</literal> script
installed in the <literal>samples</literal> subdirectory of the Mutt
documentation: it can be used as filter for <link
linkend="status-format">$status_format</link> to set the current
terminal's title, if supported.
</para>

</sect2>

<sect2 id="formatstrings-padding">
<title>Padding</title>

<para>
In most format strings, Mutt supports different types of padding using
special %-expandos:
</para>

<variablelist>
<varlistentry>
<term><literal>%|X</literal></term>
<listitem>
<para>
When this occurs, Mutt will fill the rest of the line with the character
<literal>X</literal>. For example, filling the rest of the line with
dashes is done by setting:
</para>
<screen>
set status_format = "%v on %h: %B: %?n?%n&amp;no? new messages %|-"</screen>
</listitem>
</varlistentry>
<varlistentry>
<term>
<literal>%&gt;X</literal>
</term>
<listitem>
<para>
Since the previous expando stops at the end of line, there must be a way
to fill the gap between two items via the <literal>%&gt;X</literal>
expando: it puts as many characters <literal>X</literal> in between two
items so that the rest of the line will be right-justified. For example,
to not put the version string and hostname the above example on the left
but on the right and fill the gap with spaces, one might use (note the
space after <literal>%&gt;</literal>):
</para>
<screen>
set status_format = "%B: %?n?%n&amp;no? new messages %&gt; (%v on %h)"</screen>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>%*X</literal>
</term>
<listitem>
<para>
Normal right-justification will print everything to the left of the
<literal>%&gt;</literal>, displaying padding and whatever lies to the
right only if there's room. By contrast, <quote>soft-fill</quote> gives
priority to the right-hand side, guaranteeing space to display it and
showing padding only if there's still room. If necessary, soft-fill will
eat text leftwards to make room for rightward text. For example, to
right-justify the subject making sure as much as possible of it fits on
screen, one might use (note two spaces after <literal>%* </literal>: the
second ensures there's a space between the truncated right-hand side and
the subject):
</para>
<screen>
set index_format="%4C %Z %{%b %d} %-15.15L (%?l?%4l&amp;%4c?)%*  %s"</screen>
</listitem>
</varlistentry>
</variablelist>

</sect2>

<sect2 id="formatstrings-size">
<title>Bytes size display</title>

<para>
Various format strings contain expandos that display the size of
messages in bytes.  This includes
<literal>%s</literal> in <link linkend="attach-format">$attach_format</link>,
<literal>%l</literal> in <link linkend="compose-format">$compose_format</link>,
<literal>%s</literal> in <link linkend="folder-format">$folder_format</link>,
<literal>%c</literal> in <link linkend="index-format">$index_format</link>,
and %l and %L in <link linkend="status-format">$status_format</link>.
There are four configuration variables that can be used to customize
how the numbers are displayed.
</para>

<para>
  <link linkend="size-show-bytes">$size_show_bytes</link>
  will display the number of bytes when the size is &lt; 1
  kilobyte.  When unset, kilobytes will be displayed instead.
</para>

<para>
  <link linkend="size-show-mb">$size_show_mb</link> will display the
  number of megabytes when the size is &gt;= 1 megabyte.  When
  unset, kilobytes will be displayed instead (which could be a large
  number).
</para>

<para>
  <link linkend="size-show-fractions">$size_show_fractions</link>,
  will display numbers with a single decimal place for values from
  0 to 10 kilobytes, and 1 to 10 megabytes.
</para>

<para>
  <link linkend="size-units-on-left">$size_units_on_left</link> will
  display the unit (<quote>K</quote> or <quote>M</quote>) to the left
  of the number, instead of the right if unset.
</para>

<para>
  These variables also affect size display in a few other places, such
  as progress indicators and attachment delimiters in the pager.
</para>
</sect2>

</sect1>

<sect1 id="mailto-allow">
<title>Control allowed header fields in a mailto: URL</title>

<para>Usage:</para>

<cmdsynopsis>
<command>mailto_allow</command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">header-field</replaceable>
</arg>
</group>

<command>unmailto_allow</command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">header-field</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
As a security measure, Mutt will only add user-approved header fields from a
<literal>mailto:</literal> URL.  This is necessary since Mutt will handle
certain header fields, such as <literal>Attach:</literal>, in a special way.
The <literal>mailto_allow</literal> and <literal>unmailto_allow</literal>
commands allow the user to modify the list of approved headers.
</para>
<para>
Mutt initializes the default list to contain only the <literal>Subject</literal>
and <literal>Body</literal> header fields, which are the only requirement specified
by the <literal>mailto:</literal> specification in RFC2368.
</para>
</sect1>

</chapter>

<chapter id="advancedusage">
<title>Advanced Usage</title>

<sect1 id="charset-handling">
<title>Character Set Handling</title>

<para>
A <quote>character set</quote> is basically a mapping between bytes and
glyphs and implies a certain character encoding scheme. For example, for
the ISO 8859 family of character sets, an encoding of 8bit per character
is used. For the Unicode character set, different character encodings
may be used, UTF-8 being the most popular. In UTF-8, a character is
represented using a variable number of bytes ranging from 1 to 4.
</para>

<para>
Since Mutt is a command-line tool run from a shell, and delegates
certain tasks to external tools (such as an editor for composing/editing
messages), all of these tools need to agree on a character set and
encoding. There exists no way to reliably deduce the character set a
plain text file has. Interoperability is gained by the use of
well-defined environment variables. The full set can be printed by
issuing <literal>locale</literal> on the command line.
</para>

<para>
Upon startup, Mutt determines the character set on its own using
routines that inspect locale-specific environment variables. Therefore,
it is generally not necessary to set the <literal>$charset</literal>
variable in Mutt. It may even be counter-productive as Mutt uses system
and library functions that derive the character set themselves and on
which Mutt has no influence. It's safest to let Mutt work out the locale
setup itself.
</para>

<para>
If you happen to work with several character sets on a regular basis,
it's highly advisable to use Unicode and an UTF-8 locale. Unicode can
represent nearly all characters in a message at the same time.  When not
using a Unicode locale, it may happen that you receive messages with
characters not representable in your locale. When displaying such a
message, or replying to or forwarding it, information may get lost
possibly rendering the message unusable (not only for you but also for
the recipient, this breakage is not reversible as lost information
cannot be guessed).
</para>

<para>
A Unicode locale makes all conversions superfluous which eliminates the
risk of conversion errors. It also eliminates potentially wrong
expectations about the character set between Mutt and external programs.
</para>

<para>
The terminal emulator used also must be properly configured for the
current locale. Terminal emulators usually do <emphasis>not</emphasis>
derive the locale from environment variables, they need to be configured
separately. If the terminal is incorrectly configured, Mutt may display
random and unexpected characters (question marks, octal codes, or just
random glyphs), format strings may not work as expected, you may not be
abled to enter non-ascii characters, and possible more.  Data is always
represented using bytes and so a correct setup is very important as to
the machine, all character sets <quote>look</quote> the same.
</para>

<para>
Warning: A mismatch between what system and library functions think the
locale is and what Mutt was told what the locale is may make it behave
badly with non-ascii input: it will fail at seemingly random places.
This warning is to be taken seriously since not only local mail handling
may suffer: sent messages may carry wrong character set information the
<emphasis>receiver</emphasis> has too deal with. The need to set
<literal>$charset</literal> directly in most cases points at terminal
and environment variable setup problems, not Mutt problems.
</para>

<para>
A list of officially assigned and known character sets can be found at
<ulink url="http://www.iana.org/assignments/character-sets">IANA</ulink>,
a list of locally supported locales can be obtained by running
<literal>locale -a</literal>.
</para>

</sect1>

<sect1 id="regexp">
<title>Regular Expressions</title>

<para>
All string patterns in Mutt including those in more complex <link
linkend="patterns">patterns</link> must be specified using regular
expressions (regexp) in the <quote>POSIX extended</quote> syntax (which
is more or less the syntax used by egrep and GNU awk).  For your
convenience, we have included below a brief description of this syntax.
</para>

<para>
The search is case sensitive if the pattern contains at least one upper
case letter, and case insensitive otherwise.
</para>

<note>
<para>
<quote>\</quote> must be quoted if used for a regular expression in an
initialization command: <quote>\\</quote>.
</para>
</note>

<para>
A regular expression is a pattern that describes a set of strings.
Regular expressions are constructed analogously to arithmetic
expressions, by using various operators to combine smaller expressions.
</para>

<note>
<para>
The regular expression can be enclosed/delimited by either " or ' which
is useful if the regular expression includes a white-space character.
See <xref linkend="muttrc-syntax"/> for more information on " and '
delimiter processing.  To match a literal " or ' you must preface it
with \ (backslash).
</para>
</note>

<para>
The fundamental building blocks are the regular expressions that match a
single character.  Most characters, including all letters and digits,
are regular expressions that match themselves.  Any metacharacter with
special meaning may be quoted by preceding it with a backslash.
</para>

<para>
The period <quote>.</quote> matches any single character.  The caret
<quote>^</quote> and the dollar sign <quote>$</quote> are metacharacters
that respectively match the empty string at the beginning and end of a
line.
</para>

<para>
A list of characters enclosed by <quote>[</quote> and <quote>]</quote>
matches any single character in that list; if the first character of the
list is a caret <quote>^</quote> then it matches any character
<emphasis>not</emphasis> in the list.  For example, the regular
expression <emphasis>[0123456789]</emphasis> matches any single digit.
A range of ASCII characters may be specified by giving the first and
last characters, separated by a hyphen <quote>-</quote>.  Most
metacharacters lose their special meaning inside lists.  To include a
literal <quote>]</quote> place it first in the list.  Similarly, to
include a literal <quote>^</quote> place it anywhere but first.
Finally, to include a literal hyphen <quote>-</quote> place it last.
</para>

<para>
Certain named classes of characters are predefined.  Character classes
consist of <quote>[:</quote>, a keyword denoting the class, and
<quote>:]</quote>.  The following classes are defined by the POSIX
standard in
<xref linkend="posix-regex-char-classes"/>
</para>

<table id="posix-regex-char-classes">
<title>POSIX regular expression character classes</title>
<tgroup cols="2">
<thead>
<row><entry>Character class</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>[:alnum:]</entry><entry>Alphanumeric characters</entry></row>
<row><entry>[:alpha:]</entry><entry>Alphabetic characters</entry></row>
<row><entry>[:blank:]</entry><entry>Space or tab characters</entry></row>
<row><entry>[:cntrl:]</entry><entry>Control characters</entry></row>
<row><entry>[:digit:]</entry><entry>Numeric characters</entry></row>
<row><entry>[:graph:]</entry><entry>Characters that are both printable and visible. (A space is printable, but not visible, while an <quote>a</quote> is both)</entry></row>
<row><entry>[:lower:]</entry><entry>Lower-case alphabetic characters</entry></row>
<row><entry>[:print:]</entry><entry>Printable characters (characters that are not control characters)</entry></row>
<row><entry>[:punct:]</entry><entry>Punctuation characters (characters that are not letter, digits, control characters, or space characters)</entry></row>
<row><entry>[:space:]</entry><entry>Space characters (such as space, tab and formfeed, to name a few)</entry></row>
<row><entry>[:upper:]</entry><entry>Upper-case alphabetic characters</entry></row>
<row><entry>[:xdigit:]</entry><entry>Characters that are hexadecimal digits</entry></row>
</tbody>
</tgroup>
</table>

<para>
A character class is only valid in a regular expression inside the
brackets of a character list.
</para>

<note>
<para>
Note that the brackets in these class names are part of the symbolic
names, and must be included in addition to the brackets delimiting the
bracket list. For example, <emphasis>[[:digit:]]</emphasis> is
equivalent to <emphasis>[0-9]</emphasis>.
</para>
</note>

<para>
Two additional special sequences can appear in character lists.  These
apply to non-ASCII character sets, which can have single symbols (called
collating elements) that are represented with more than one character,
as well as several characters that are equivalent for collating or
sorting purposes:
</para>

<variablelist>

<varlistentry>
<term>Collating Symbols</term>
<listitem>
<para>
A collating symbol is a multi-character collating element enclosed in
<quote>[.</quote> and <quote>.]</quote>.  For example, if
<quote>ch</quote> is a collating element, then
<emphasis>[[.ch.]]</emphasis> is a regexp that matches this collating
element, while <emphasis>[ch]</emphasis> is a regexp that matches either
<quote>c</quote> or <quote>h</quote>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Equivalence Classes</term>
<listitem>
<para>
An equivalence class is a locale-specific name for a list of characters
that are equivalent. The name is enclosed in <quote>[=</quote> and
<quote>=]</quote>.  For example, the name <quote>e</quote> might be used
to represent all of <quote>e</quote> with grave
(<quote>&egrave;</quote>), <quote>e</quote> with acute
(<quote>&eacute;</quote>) and <quote>e</quote>.  In this case,
<emphasis>[[=e=]]</emphasis> is a regexp that matches any of:
<quote>e</quote> with grave (<quote>&egrave;</quote>), <quote>e</quote>
with acute (<quote>&eacute;</quote>) and <quote>e</quote>.
</para>
</listitem>
</varlistentry>
</variablelist>

<para>
A regular expression matching a single character may be followed by one
of several repetition operators described in <xref
linkend="regex-repeat"/>.
</para>

<table id="regex-repeat">
<title>Regular expression repetition operators</title>
<tgroup cols="2">
<thead>
<row><entry>Operator</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>?</entry><entry>The preceding item is optional and matched at most once</entry></row>
<row><entry>*</entry><entry>The preceding item will be matched zero or more times</entry></row>
<row><entry>+</entry><entry>The preceding item will be matched one or more times</entry></row>
<row><entry>{n}</entry><entry>The preceding item is matched exactly <emphasis>n</emphasis> times</entry></row>
<row><entry>{n,}</entry><entry>The preceding item is matched <emphasis>n</emphasis> or more times</entry></row>
<row><entry>{,m}</entry><entry>The preceding item is matched at most <emphasis>m</emphasis> times</entry></row>
<row><entry>{n,m}</entry><entry>The preceding item is matched at least <emphasis>n</emphasis> times, but no more than <emphasis>m</emphasis> times</entry></row>
</tbody>
</tgroup>
</table>

<para>
Two regular expressions may be concatenated; the resulting regular
expression matches any string formed by concatenating two substrings
that respectively match the concatenated subexpressions.
</para>

<para>
Two regular expressions may be joined by the infix operator
<quote>|</quote>; the resulting regular expression matches any string
matching either subexpression.
</para>

<para>
Repetition takes precedence over concatenation, which in turn takes
precedence over alternation.  A whole subexpression may be enclosed in
parentheses to override these precedence rules.
</para>

<note>
<para>
If you compile Mutt with the included regular expression engine, the
following operators may also be used in regular expressions as described
in <xref linkend="regex-gnu-ext"/>.
</para>
</note>

<table id="regex-gnu-ext">
<title>GNU regular expression extensions</title>
<tgroup cols="2">
<thead>
<row><entry>Expression</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>\\y</entry><entry>Matches the empty string at either the beginning or the end of a word</entry></row>
<row><entry>\\B</entry><entry>Matches the empty string within a word</entry></row>
<row><entry>\\&lt;</entry><entry>Matches the empty string at the beginning of a word</entry></row>
<row><entry>\\&gt;</entry><entry>Matches the empty string at the end of a word</entry></row>
<row><entry>\\w</entry><entry>Matches any word-constituent character (letter, digit, or underscore)</entry></row>
<row><entry>\\W</entry><entry>Matches any character that is not word-constituent</entry></row>
<row><entry>\\`</entry><entry>Matches the empty string at the beginning of a buffer (string)</entry></row>
<row><entry>\\'</entry><entry>Matches the empty string at the end of a buffer</entry></row>
</tbody>
</tgroup>
</table>

<para>
Please note however that these operators are not defined by POSIX, so
they may or may not be available in stock libraries on various systems.
</para>

</sect1>

<sect1 id="patterns">
<title>Patterns: Searching, Limiting and Tagging</title>

<sect2 id="patterns-modifier">
<title>Pattern Modifier</title>

<para>
Many of Mutt's commands allow you to specify a pattern to match
(<literal>limit</literal>, <literal>tag-pattern</literal>,
<literal>delete-pattern</literal>, etc.). <xref linkend="tab-patterns"/>
shows several ways to select messages.
</para>

<table id="tab-patterns">
<title>Pattern modifiers</title>
<tgroup cols="2">
<thead>
<row><entry>Pattern modifier</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>~A</entry><entry>all messages</entry></row>
<row><entry>~b <emphasis>EXPR</emphasis></entry><entry>messages which contain <emphasis>EXPR</emphasis> in the message body ***)</entry></row>
<row><entry>=b <emphasis>STRING</emphasis></entry><entry>If IMAP is enabled, like ~b but searches for <emphasis>STRING</emphasis> on the server, rather than downloading each message and searching it locally.</entry></row>
<row><entry>~B <emphasis>EXPR</emphasis></entry><entry>messages which contain <emphasis>EXPR</emphasis> in the whole message ***)</entry></row>
<row><entry>=B <emphasis>STRING</emphasis></entry><entry>If IMAP is enabled, like ~B but searches for <emphasis>STRING</emphasis> on the server, rather than downloading each message and searching it locally.</entry></row>
<row><entry>~c <emphasis>EXPR</emphasis></entry><entry>messages carbon-copied to <emphasis>EXPR</emphasis></entry></row>
<row><entry>%c <emphasis>GROUP</emphasis></entry><entry>messages carbon-copied to any member of <emphasis>GROUP</emphasis></entry></row>
<row><entry>~C <emphasis>EXPR</emphasis></entry><entry>messages either to: or cc: <emphasis>EXPR</emphasis></entry></row>
<row><entry>%C <emphasis>GROUP</emphasis></entry><entry>messages either to: or cc: to any member of <emphasis>GROUP</emphasis></entry></row>
<row><entry>~d [<emphasis>MIN</emphasis>]-[<emphasis>MAX</emphasis>]</entry><entry>messages with <quote>date-sent</quote> in a Date range</entry></row>
<row><entry>~D</entry><entry>deleted messages</entry></row>
<row><entry>~e <emphasis>EXPR</emphasis></entry><entry>messages which contains <emphasis>EXPR</emphasis> in the <quote>Sender</quote> field</entry></row>
<row><entry>%e <emphasis>GROUP</emphasis></entry><entry>messages which contain a member of <emphasis>GROUP</emphasis> in the <quote>Sender</quote> field</entry></row>
<row><entry>~E</entry><entry>expired messages</entry></row>
<row><entry>~F</entry><entry>flagged messages</entry></row>
<row><entry>~f <emphasis>EXPR</emphasis></entry><entry>messages originating from <emphasis>EXPR</emphasis></entry></row>
<row><entry>%f <emphasis>GROUP</emphasis></entry><entry>messages originating from any member of <emphasis>GROUP</emphasis></entry></row>
<row><entry>~g</entry><entry>cryptographically signed messages</entry></row>
<row><entry>~G</entry><entry>cryptographically encrypted messages</entry></row>
<row><entry>~h <emphasis>EXPR</emphasis></entry><entry>messages which contain <emphasis>EXPR</emphasis> in the message header ***)</entry></row>
<row><entry>=h <emphasis>STRING</emphasis></entry><entry>If IMAP is enabled, like ~h but searches for <emphasis>STRING</emphasis> on the server, rather than downloading each message and searching it locally; <emphasis>STRING</emphasis> must be of the form <quote>header: substring</quote> (see below).</entry></row>
<row><entry>~H <emphasis>EXPR</emphasis></entry><entry>messages with a spam attribute matching <emphasis>EXPR</emphasis></entry></row>
<row><entry>~i <emphasis>EXPR</emphasis></entry><entry>messages which match <emphasis>EXPR</emphasis> in the <quote>Message-ID</quote> field</entry></row>
<row><entry>~k</entry><entry>messages which contain PGP key material</entry></row>
<row><entry>~L <emphasis>EXPR</emphasis></entry><entry>messages either originated or received by <emphasis>EXPR</emphasis></entry></row>
<row><entry>%L <emphasis>GROUP</emphasis></entry><entry>message either originated or received by any member of <emphasis>GROUP</emphasis></entry></row>
<row><entry>~l</entry><entry>messages addressed to a known mailing list</entry></row>
<row><entry>~m [<emphasis>MIN</emphasis>]-[<emphasis>MAX</emphasis>]</entry><entry>messages in the range <emphasis>MIN</emphasis> to <emphasis>MAX</emphasis> *)</entry></row>
<row><entry>~M <emphasis>EXPR</emphasis></entry><entry>messages which contain a mime Content-Type matching <emphasis>EXPR</emphasis> ***)</entry></row>
<row><entry>~n [<emphasis>MIN</emphasis>]-[<emphasis>MAX</emphasis>]</entry><entry>messages with a score in the range <emphasis>MIN</emphasis> to <emphasis>MAX</emphasis> *)</entry></row>
<row><entry>~N</entry><entry>new messages</entry></row>
<row><entry>~O</entry><entry>old messages</entry></row>
<row>
<entry>~p</entry>
<entry>messages addressed to you (consults <link linkend="from">$from</link>, <command>alternates</command>, and local account/hostname information)</entry>
</row>
<row>
<entry>~P</entry>
<entry>messages from you (consults <link linkend="from">$from</link>, <command>alternates</command>, and local account/hostname information)</entry>
</row>
<row><entry>~Q</entry><entry>messages which have been replied to</entry></row>
<row><entry>~r [<emphasis>MIN</emphasis>]-[<emphasis>MAX</emphasis>]</entry><entry>messages with <quote>date-received</quote> in a Date range</entry></row>
<row><entry>~R</entry><entry>read messages</entry></row>
<row><entry>~s <emphasis>EXPR</emphasis></entry><entry>messages having <emphasis>EXPR</emphasis> in the <quote>Subject</quote> field.</entry></row>
<row><entry>~S</entry><entry>superseded messages</entry></row>
<row><entry>~t <emphasis>EXPR</emphasis></entry><entry>messages addressed to <emphasis>EXPR</emphasis></entry></row>
<row><entry>~T</entry><entry>tagged messages</entry></row>
<row><entry>~u</entry><entry>messages addressed to a subscribed mailing list</entry></row>
<row><entry>~U</entry><entry>unread messages</entry></row>
<row><entry>~v</entry><entry>messages part of a collapsed thread.</entry></row>
<row><entry>~V</entry><entry>cryptographically verified messages</entry></row>
<row><entry>~x <emphasis>EXPR</emphasis></entry><entry>messages which contain <emphasis>EXPR</emphasis> in the <quote>References</quote> or <quote>In-Reply-To</quote> field</entry></row>
<row><entry>~X [<emphasis>MIN</emphasis>]-[<emphasis>MAX</emphasis>]</entry><entry>messages with <emphasis>MIN</emphasis> to <emphasis>MAX</emphasis> attachments *) ***)</entry></row>
<row><entry>~y <emphasis>EXPR</emphasis></entry><entry>messages which contain <emphasis>EXPR</emphasis> in the <quote>X-Label</quote> field</entry></row>
<row><entry>~z [<emphasis>MIN</emphasis>]-[<emphasis>MAX</emphasis>]</entry><entry>messages with a size in the range <emphasis>MIN</emphasis> to <emphasis>MAX</emphasis> *) **)</entry></row>
<row><entry>~=</entry><entry>duplicated messages (see <link linkend="duplicate-threads">$duplicate_threads</link>)</entry></row>
<row><entry>~$</entry><entry>unreferenced messages (requires threaded view)</entry></row>
<row><entry>~(<emphasis>PATTERN</emphasis>)</entry><entry>messages in threads
containing messages matching <emphasis>PATTERN</emphasis>, e.g. all
threads containing messages from you: ~(~P)</entry></row>
<row><entry>~&lt;(<emphasis>PATTERN</emphasis>)</entry><entry>messages
whose immediate parent matches <emphasis>PATTERN</emphasis>,
e.g. replies to your messages: ~&lt;(~P)</entry></row>
<row><entry>~&gt;(<emphasis>PATTERN</emphasis>)</entry><entry>messages
having an immediate child matching <emphasis>PATTERN</emphasis>,
e.g. messages you replied to: ~&gt;(~P)</entry></row>
</tbody>
</tgroup>
</table>

<para>
Where <emphasis>EXPR</emphasis> is a <link linkend="regexp">regular expression</link>, and <emphasis>GROUP</emphasis> is an
<link linkend="addrgroup">address group</link>.
</para>

<para>
*) The forms <quote>&lt;[<emphasis>MAX</emphasis>]</quote>,
<quote>&gt;[<emphasis>MIN</emphasis>]</quote>,
<quote>[<emphasis>MIN</emphasis>]-</quote> and
<quote>-[<emphasis>MAX</emphasis>]</quote> are allowed, too.
</para>

<para>
**) The suffixes <quote>K</quote> and <quote>M</quote> are allowed to
specify kilobyte and megabyte respectively.
</para>

<para>
***) These patterns read each message in, and can therefore be much
slower.  Over IMAP this will entail downloading each message.  They
can not be used for <link linkend="score-command">message
scoring</link>, and it is recommended to avoid using them for index
coloring.
</para>

<para>
Special attention has to be paid when using regular expressions inside
of patterns.  Specifically, Mutt's parser for these patterns will strip
one level of backslash (<quote>\</quote>), which is normally used for
quoting.  If it is your intention to use a backslash in the regular
expression, you will need to use two backslashes instead
(<quote>\\</quote>).
</para>

<para>
You can force Mutt to treat
<emphasis>EXPR</emphasis> as a simple string instead of a regular
expression by using = instead of ~ in the pattern name. For example,
<literal>=b *.*</literal> will find all messages that contain the
literal string <quote>*.*</quote>. Simple string matches are less
powerful than regular expressions but can be considerably faster.
</para>

<para>
For IMAP folders, string matches <literal>=b</literal>,
<literal>=B</literal>, and <literal>=h</literal> will be performed on
the server instead of by fetching every message. IMAP treats
<literal>=h</literal> specially: it must be of the form <quote>header:
substring</quote> and will not partially match header names. The
substring part may be omitted if you simply wish to find messages
containing a particular header without regard to its value.
</para>

<para>
Patterns matching lists of addresses (notably c, C, p, P and t) match if
there is at least one match in the whole list. If you want to make sure
that all elements of that list match, you need to prefix your pattern
with <quote>^</quote>.  This example matches all mails which only has
recipients from Germany.
</para>

<example id="ex-recips">
<title>Matching all addresses in address lists</title>
<screen>
^~C \.de$
</screen>
</example>

<para>
You can restrict address pattern matching to aliases that you have
defined with the "@" modifier.  This example matches messages whose
recipients are all from Germany, and who are known to your alias list.
</para>

<example id="ex-restrict-to-aliases">
<title>Matching restricted to aliases</title>
<screen>
^@~C \.de$
</screen>
</example>

<para>
To match any defined alias, use a regular expression that matches any
string.  This example matches messages whose senders are known aliases.
</para>

<example id="ex-match-alias">
<title>Matching any defined alias</title>
<screen>
@~f .
</screen>
</example>

</sect2>

<sect2 id="simple-searches">
<title>Simple Searches</title>

<para>
Mutt supports two versions of so called <quote>simple
searches</quote>. These are issued if the query entered for searching,
limiting and similar operations does not seem to contain a valid pattern
modifier (i.e. it does not contain one of these characters:
<quote>~</quote>, <quote>=</quote> or <quote>%</quote>). If the query is
supposed to contain one of these special characters, they must be
escaped by prepending a backslash (<quote>\</quote>).
</para>

<para>
The first type is by checking whether the query string equals
a keyword case-insensitively from <xref linkend="tab-simplesearch-keywords"/>:
If that is the case, Mutt will use the shown pattern modifier instead.
If a keyword would conflict with your search keyword, you need to turn
it into a regular expression to avoid matching the keyword table. For
example, if you want to find all messages matching <quote>flag</quote>
(using <link linkend="simple-search">$simple_search</link>)
but don't want to match flagged messages, simply search for
<quote><literal>[f]lag</literal></quote>.
</para>

<table id="tab-simplesearch-keywords">
<title>Simple search keywords</title>
<tgroup cols="2">
<thead>
<row><entry>Keyword</entry><entry>Pattern modifier</entry></row>
</thead>
<tbody>
<row><entry>all</entry><entry>~A</entry></row>
<row><entry>.</entry><entry>~A</entry></row>
<row><entry>^</entry><entry>~A</entry></row>
<row><entry>del</entry><entry>~D</entry></row>
<row><entry>flag</entry><entry>~F</entry></row>
<row><entry>new</entry><entry>~N</entry></row>
<row><entry>old</entry><entry>~O</entry></row>
<row><entry>repl</entry><entry>~Q</entry></row>
<row><entry>read</entry><entry>~R</entry></row>
<row><entry>tag</entry><entry>~T</entry></row>
<row><entry>unread</entry><entry>~U</entry></row>
</tbody>
</tgroup>
</table>

<para>
The second type of simple search is to build a complex search pattern
using <link linkend="simple-search">$simple_search</link> as a
template. Mutt will insert your query properly quoted and search for the
composed complex query.
</para>

</sect2>

<sect2 id="complex-patterns">
<title>Nesting and Boolean Operators</title>

<para>
Logical AND is performed by specifying more than one criterion.  For
example:
</para>

<screen>
~t mutt ~f elkins
</screen>

<para>
would select messages which contain the word <quote>mutt</quote> in the
list of recipients <emphasis>and</emphasis> that have the word
<quote>elkins</quote> in the <quote>From</quote> header field.
</para>

<para>
Mutt also recognizes the following operators to create more complex
search patterns:
</para>

<itemizedlist>
<listitem>

<para>
! &mdash; logical NOT operator
</para>
</listitem>
<listitem>

<para>
| &mdash; logical OR operator
</para>
</listitem>
<listitem>

<para>
() &mdash; logical grouping operator
</para>
</listitem>

</itemizedlist>

<para>
Here is an example illustrating a complex search pattern.  This pattern
will select all messages which do not contain <quote>mutt</quote> in the
<quote>To</quote> or <quote>Cc</quote> field and which are from
<quote>elkins</quote>.
</para>

<example id="ex-pattern-bool">
<title>Using boolean operators in patterns</title>
<screen>
!(~t mutt|~c mutt) ~f elkins
</screen>
</example>

<para>
Here is an example using white space in the regular expression (note the
<quote>'</quote> and <quote>"</quote> delimiters).  For this to match,
the mail's subject must match the <quote>^Junk +From +Me$</quote> and it
must be from either <quote>Jim +Somebody</quote> or <quote>Ed
+SomeoneElse</quote>:
</para>

<screen>
'~s "^Junk +From +Me$" ~f ("Jim +Somebody"|"Ed +SomeoneElse")'
</screen>

<note>
<para>
If a regular expression contains parenthesis, or a vertical bar ("|"),
you <emphasis>must</emphasis> enclose the expression in double or single
quotes since those characters are also used to separate different parts
of Mutt's pattern language.  For example: <literal>~f
"me@(mutt\.org|cs\.hmc\.edu)"</literal> Without the quotes, the
parenthesis wouldn't end.  This would be separated to two OR'd patterns:
<emphasis>~f me@(mutt\.org</emphasis> and
<emphasis>cs\.hmc\.edu)</emphasis>. They are never what you want.
</para>
</note>

</sect2>

<sect2 id="date-patterns">
<title>Searching by Date</title>

<para>
Mutt supports two types of dates, <emphasis>absolute</emphasis> and
<emphasis>relative</emphasis>.
</para>

<sect3 id="date-absolute">
<title>Absolute Dates</title>

<para>
Dates <emphasis>must</emphasis> be in DD/MM/YY format (month and year
are optional, defaulting to the current month and year) or YYYYMMDD.  An
example of a valid range of dates is:
</para>

<screen>
Limit to messages matching: ~d 20/1/95-31/10
Limit to messages matching: ~d 19950120-19951031
</screen>

<para>
If you omit the minimum (first) date, and just specify
<quote>-DD/MM/YY</quote> or <quote>-YYYYMMDD</quote>, all messages
<emphasis>before</emphasis> the given date will be selected.  If you omit the
maximum (second) date, and specify <quote>DD/MM/YY-</quote>, all messages
<emphasis>after</emphasis> the given date will be selected.  If you
specify a single date with no dash (<quote>-</quote>), only messages
sent on the given date will be selected.
</para>

<para>
You can add error margins to absolute dates.  An error margin is a sign
(+ or -), followed by a digit, followed by one of the units in <xref
linkend="tab-date-units"/>. As a special case, you can replace the sign
by a <quote>*</quote> character, which is equivalent to giving identical
plus and minus error margins.
</para>

<table id="tab-date-units">
<title>Date units</title>
<tgroup cols="2">
<thead>
<row><entry>Unit</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>y</entry><entry>Years</entry></row>
<row><entry>m</entry><entry>Months</entry></row>
<row><entry>w</entry><entry>Weeks</entry></row>
<row><entry>d</entry><entry>Days</entry></row>
</tbody>
</tgroup>
</table>

<para>
Example: To select any messages two weeks around January 15, 2001, you'd
use the following pattern:
</para>

<screen>
Limit to messages matching: ~d 15/1/2001*2w
</screen>

</sect3>

<sect3 id="dates-relative">
<title>Relative Dates</title>

<para>
This type of date is relative to the current date, and may be specified
as:
</para>

<itemizedlist>
<listitem>

<para>
&gt;<emphasis>offset</emphasis> for messages older than
<emphasis>offset</emphasis> units
</para>
</listitem>
<listitem>

<para>
&lt;<emphasis>offset</emphasis> for messages newer than
<emphasis>offset</emphasis> units
</para>
</listitem>
<listitem>

<para>
=<emphasis>offset</emphasis> for messages exactly
<emphasis>offset</emphasis> units old
</para>
</listitem>

</itemizedlist>

<para>
<emphasis>offset</emphasis> is specified as a positive number with one
of the units from <xref linkend="tab-rel-date-units"/>.
</para>

<table id="tab-rel-date-units">
<title>Relative date units</title>
<tgroup cols="2">
<thead>
<row><entry>Unit</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>y</entry><entry>Years</entry></row>
<row><entry>m</entry><entry>Months</entry></row>
<row><entry>w</entry><entry>Weeks</entry></row>
<row><entry>d</entry><entry>Days</entry></row>
<row><entry>H</entry><entry>Hours</entry></row>
<row><entry>M</entry><entry>Minutes</entry></row>
<row><entry>S</entry><entry>Seconds</entry></row>
</tbody>
</tgroup>
</table>

<para>
Example: to select messages less than 1 month old, you would use
</para>

<screen>
Limit to messages matching: ~d &lt;1m
</screen>

<note>
<para>
All dates used when searching are relative to the
<emphasis>local</emphasis> time zone, so unless you change the setting
of your <link linkend="index-format">$index_format</link> to include a
<literal>%[...]</literal> format, these are <emphasis>not</emphasis> the
dates shown in the main index.
</para>
</note>

</sect3>

</sect2>

</sect1>

<sect1 id="markmsg">
<title>Marking Messages</title>

<para>
There are times that it's useful to ask Mutt to "remember" which message
you're currently looking at, while you move elsewhere in your mailbox.
You can do this with the <quote>mark-message</quote> operator, which
is bound to the <quote>~</quote> key by default.  Press this key to
enter an identifier for the marked message. When you want to return to
this message, press <quote>'</quote> and the name that you previously
entered.
</para>

<para>
(Message marking is really just a shortcut for defining a macro
that returns you to the current message by searching for its
Message-ID.  You can choose a different prefix by setting the <link
linkend="mark-macro-prefix">$mark_macro_prefix</link> variable.)
</para>
</sect1>

<sect1 id="tags">
<title>Using Tags</title>

<para>
Sometimes it is desirable to perform an operation on a group of messages
all at once rather than one at a time.  An example might be to save
messages to a mailing list to a separate folder, or to delete all
messages with a given subject.  To tag all messages matching a pattern,
use the <literal>&lt;tag-pattern&gt;</literal> function, which is bound
to <quote>shift-T</quote> by default.  Or you can select individual
messages by hand using the <literal>&lt;tag-message&gt;</literal>
function, which is bound to <quote>t</quote> by default.  See <link
linkend="patterns">patterns</link> for Mutt's pattern matching syntax.
</para>

<para>
Once you have tagged the desired messages, you can use the
<quote>tag-prefix</quote> operator, which is the <quote>;</quote>
(semicolon) key by default.  When the <quote>tag-prefix</quote> operator
is used, the <emphasis>next</emphasis> operation will be applied to all
tagged messages if that operation can be used in that manner.  If the
<link linkend="auto-tag">$auto_tag</link> variable is set, the next
operation applies to the tagged messages automatically, without
requiring the <quote>tag-prefix</quote>.
</para>

<para>
In <link linkend="macro"><command>macro</command>s</link> or <link
linkend="push"><command>push</command></link> commands, you can use the
<literal>&lt;tag-prefix-cond&gt;</literal> operator.  If there are no
tagged messages, Mutt will <quote>eat</quote> the rest of the macro to
abort it's execution.  Mutt will stop <quote>eating</quote> the macro
when it encounters the <literal>&lt;end-cond&gt;</literal> operator;
after this operator the rest of the macro will be executed as normal.
</para>

</sect1>

<sect1 id="hooks">
<title>Using Hooks</title>

<para>
A <emphasis>hook</emphasis> is a concept found in many other programs
which allows you to execute arbitrary commands before performing some
operation.  For example, you may wish to tailor your configuration based
upon which mailbox you are reading, or to whom you are sending mail.  In
the Mutt world, a <emphasis>hook</emphasis> consists of a <link
linkend="regexp">regular expression</link> or <link
linkend="patterns">pattern</link> along with a configuration
option/command.  See:

<itemizedlist>

<listitem>
<para>
<link linkend="account-hook"><command>account-hook</command></link>
</para>
</listitem>

<listitem>
<para>
<link linkend="charset-hook"><command>charset-hook</command></link>
</para>
</listitem>

<listitem>
<para>
<link linkend="crypt-hook"><command>crypt-hook</command></link>
</para>
</listitem>

<listitem>
<para>
<link linkend="fcc-hook"><command>fcc-hook</command></link>
</para>
</listitem>

<listitem>
<para>
<link linkend="fcc-save-hook"><command>fcc-save-hook</command></link>
</para>
</listitem>

<listitem>
<para>
<link linkend="folder-hook"><command>folder-hook</command></link>
</para>
</listitem>

<listitem>
<para>
<link linkend="charset-hook"><command>iconv-hook</command></link>
</para>
</listitem>

<listitem>
<para>
<link linkend="index-format-hook"><command>index-format-hook</command></link>
</para>
</listitem>

<listitem>
<para>
<link linkend="mbox-hook"><command>mbox-hook</command></link>
</para>
</listitem>

<listitem>
<para>
<link linkend="message-hook"><command>message-hook</command></link>
</para>
</listitem>

<listitem>
<para>
<link linkend="reply-hook"><command>reply-hook</command></link>
</para>
</listitem>

<listitem>
<para>
<link linkend="save-hook"><command>save-hook</command></link>
</para>
</listitem>

<listitem>
<para>
<link linkend="send-hook"><command>send-hook</command></link>
</para>
</listitem>

<listitem>
<para>
<link linkend="send2-hook"><command>send2-hook</command></link>
</para>
</listitem>

</itemizedlist>

for specific details on each type of <emphasis>hook</emphasis> available.
Also see <link linkend="compose-flow">Message Composition Flow</link> for
an overview of the composition process.
</para>

<note>
<para>
If a hook changes configuration settings, these changes remain effective
until the end of the current Mutt session. As this is generally not
desired, a <quote>default</quote> hook needs to be added before all
other hooks of that type to restore configuration defaults.
</para>
</note>

<example id="ex-default-hook">
<title>Specifying a <quote>default</quote> hook</title>
<screen>
send-hook . 'unmy_hdr From:'
send-hook ~C'^b@b\.b$' my_hdr from: c@c.c
</screen>
</example>

<para>
In <xref linkend="ex-default-hook"/>, by default the value of <link
linkend="from">$from</link> and <link
linkend="realname">$realname</link> is not overridden. When sending
messages either To: or Cc: to <literal>&lt;b@b.b&gt;</literal>, the
From: header is changed to <literal>&lt;c@c.c&gt;</literal>.
</para>

<sect2 id="pattern-hook" xreflabel="Message Matching in Hooks">
<title>Message Matching in Hooks</title>

<para>
Hooks that act upon messages (<command>message-hook</command>,
<command>reply-hook</command>, <command>send-hook</command>,
<command>send2-hook</command>, <command>save-hook</command>,
<command>fcc-hook</command>, <command>index-format-hook</command>)
are evaluated in a slightly different
manner. For the other types of hooks, a <link linkend="regexp">regular
expression</link> is sufficient.  But in dealing with messages a finer
grain of control is needed for matching since for different purposes you
want to match different criteria.
</para>

<para>
Mutt allows the use of the <link linkend="patterns">search
pattern</link> language for matching messages in hook commands.  This
works in exactly the same way as it would when
<emphasis>limiting</emphasis> or <emphasis>searching</emphasis> the
mailbox, except that you are restricted to those operators which match
information Mutt extracts from the header of the message (i.e., from,
to, cc, date, subject, etc.).
</para>

<para>
For example, if you wanted to set your return address based upon sending
mail to a specific address, you could do something like:
</para>

<screen>
send-hook '~t ^me@cs\.hmc\.edu$' 'my_hdr From: Mutt User &lt;user@host&gt;'
</screen>

<para>
which would execute the given command when sending mail to
<emphasis>me@cs.hmc.edu</emphasis>.
</para>

<para>
However, it is not required that you write the pattern to match using
the full searching language.  You can still specify a simple
<emphasis>regular expression</emphasis> like the other hooks, in which
case Mutt will translate your pattern into the full language, using the
translation specified by the <link
linkend="default-hook">$default_hook</link> variable.  The pattern is
translated at the time the hook is declared, so the value of <link
linkend="default-hook">$default_hook</link> that is in effect at that
time will be used.
</para>

</sect2>

<sect2 id="mailbox-hook" xreflabel="Mailbox Matching in Hooks">
<title>Mailbox Matching in Hooks</title>

<para>
Hooks that match against mailboxes (<command>folder-hook</command>,
<command>mbox-hook</command>) apply both <link linkend="regexp">regular
expression</link> syntax as well as <link linkend="shortcuts">mailbox
shortcut</link> expansion on the regexp parameter.  There is some
overlap between these, so special attention should be paid to the first
character of the regexp.
</para>

<screen>
# Here, ^ will expand to "the current mailbox" not "beginning of string":
folder-hook ^/home/user/Mail/bar "set sort=threads"

# If you want ^ to be interpreted as "beginning of string", one workaround
# is to enclose the regexp in parenthesis:
folder-hook (^/home/user/Mail/bar) "set sort=threads"

# This will expand to the default save folder for the alias "imap.example.com", which
# is probably not what you want:
folder-hook @imap.example.com "set sort=threads"

# A workaround is to use parenthesis or a backslash:
folder-hook (@imap.example.com) "set sort=threads"
folder-hook '\@imap.example.com' "set sort=threads"
</screen>

<para>
Keep in mind that mailbox shortcut expansion on the regexp parameter
takes place when the hook is initially parsed, not when the hook is
matching against a mailbox.  When Mutt starts up and is reading the
.muttrc, some mailbox shortcuts may not be usable.  For example, the
"current mailbox" shortcut, ^, will expand to an empty string because no
mailbox has been opened yet.  Mutt will issue an error for this case or
if the mailbox shortcut results in an empty regexp.
</para>

</sect2>

</sect1>

<sect1 id="setenv">
<title>Managing the Environment</title>

<para>
You can alter the environment that Mutt passes on to its child processes
using the <quote>setenv</quote> and <quote>unsetenv</quote> operators.
(N.B. These follow Mutt-style syntax, not shell-style!)  You can also
query current environment values by prefixing a <quote>?</quote> character.
</para>

<screen>
setenv TERM vt100
setenv ORGANIZATION "The Mutt Development Team"
unsetenv DISPLAY
setenv ?LESS
</screen>
</sect1>

<sect1 id="query">
<title>External Address Queries</title>

<para>
Mutt supports connecting to external directory databases such as LDAP,
ph/qi, bbdb, or NIS through a wrapper script which connects to Mutt
using a simple interface.  Using the <link
linkend="query-command">$query_command</link> variable, you specify the
wrapper command to use.  For example:
</para>

<screen>
set query_command = "mutt_ldap_query.pl %s"
</screen>

<para>
The wrapper script should accept the query on the command-line.  It
should return a one line message, then each matching response on a
single line, each line containing a tab separated address then name then
some other optional information.  On error, or if there are no matching
addresses, return a non-zero exit code and a one line error message.
</para>

<para>
An example multiple response output:
</para>

<screen>
Searching database ... 20 entries ... 3 matching:
me@cs.hmc.edu           Michael Elkins  mutt dude
blong@fiction.net       Brandon Long    mutt and more
roessler@does-not-exist.org        Thomas Roessler mutt pgp
</screen>

<para>
There are two mechanisms for accessing the query function of Mutt.  One
is to do a query from the index menu using the
<literal>&lt;query&gt;</literal> function (default: Q).  This will
prompt for a query, then bring up the query menu which will list the
matching responses.  From the query menu, you can select addresses to
create aliases, or to mail.  You can tag multiple addresses to mail,
start a new query, or have a new query appended to the current
responses.
</para>

<para>
The other mechanism for accessing the query function is for address
completion, similar to the alias completion.  In any prompt for address
entry, you can use the <literal>&lt;complete-query&gt;</literal>
function (default: ^T) to run a query based on the current address you
have typed.  Like aliases, Mutt will look for what you have typed back
to the last space or comma.  If there is a single response for that
query, Mutt will expand the address in place.  If there are multiple
responses, Mutt will activate the query menu.  At the query menu, you
can select one or more addresses to be added to the prompt.
</para>

</sect1>

<sect1 id="mailbox-formats">
<title>Mailbox Formats</title>

<para>
Mutt supports reading and writing of four different local mailbox
formats: mbox, MMDF, MH and Maildir.  The mailbox type is auto detected,
so there is no need to use a flag for different mailbox types.  When
creating new mailboxes, Mutt uses the default specified with the <link
linkend="mbox-type">$mbox_type</link> variable. A short description of
the formats follows.
</para>

<para>
<emphasis>mbox</emphasis>.  This is a widely used mailbox format for
UNIX.  All messages are stored in a single file.  Each message has a
line of the form:
</para>

<screen>
From me@cs.hmc.edu Fri, 11 Apr 1997 11:44:56 PST
</screen>

<para>
to denote the start of a new message (this is often referred to as the
<quote>From_</quote> line). The mbox format requires mailbox locking, is
prone to mailbox corruption with concurrently writing clients or
misinterpreted From_ lines. Depending on the environment, new mail
detection can be unreliable. Mbox folders are fast to open and easy to
archive.
</para>

<para>
<emphasis>MMDF</emphasis>.  This is a variant of the
<emphasis>mbox</emphasis> format.  Each message is surrounded by lines
containing <quote>^A^A^A^A</quote> (four times control-A's). The same
problems as for mbox apply (also with finding the right message
separator as four control-A's may appear in message bodies).
</para>

<para>
<emphasis>MH</emphasis>. A radical departure from
<emphasis>mbox</emphasis> and <emphasis>MMDF</emphasis>, a mailbox
consists of a directory and each message is stored in a separate file.
The filename indicates the message number (however, this is may not
correspond to the message number Mutt displays). Deleted messages are
renamed with a comma (<quote>,</quote>) prepended to the filename. Mutt
detects this type of mailbox by looking for either
<literal>.mh_sequences</literal> or <literal>.xmhcache</literal> files
(needed to distinguish normal directories from MH mailboxes). MH is more
robust with concurrent clients writing the mailbox, but still may suffer
from lost flags; message corruption is less likely to occur than with
mbox/mmdf. It's usually slower to open compared to mbox/mmdf since many
small files have to be read (Mutt provides <xref
linkend="header-caching"/> to greatly speed this process up).  Depending
on the environment, MH is not very disk-space efficient.
</para>

<para>
<emphasis>Maildir</emphasis>.  The newest of the mailbox formats, used
by the Qmail MTA (a replacement for sendmail).  Similar to
<emphasis>MH</emphasis>, except that it adds three subdirectories of the
mailbox: <emphasis>tmp</emphasis>, <emphasis>new</emphasis> and
<emphasis>cur</emphasis>.  Filenames for the messages are chosen in such
a way they are unique, even when two programs are writing the mailbox
over NFS, which means that no file locking is needed and corruption is
very unlikely. Maildir maybe slower to open without caching in Mutt, it
too is not very disk-space efficient depending on the environment. Since
no additional files are used for metadata (which is embedded in the
message filenames) and Maildir is locking-free, it's easy to sync across
different machines using file-level synchronization tools.
</para>

</sect1>

<sect1 id="shortcuts">
<title>Mailbox Shortcuts</title>

<para>
There are a number of built in shortcuts which refer to specific
mailboxes.  These shortcuts can be used anywhere you are prompted for a
file or mailbox path or in path-related configuration variables. Note
that these only work at the beginning of a string.
</para>

<table id="tab-mailbox-shortcuts">
<title>Mailbox shortcuts</title>
<tgroup cols="2">
<thead>
<row><entry>Shortcut</entry><entry>Refers to...</entry></row>
</thead>
<tbody>
<row><entry><literal>!</literal></entry><entry>your <link linkend="spoolfile">$spoolfile</link> (incoming) mailbox</entry></row>
<row><entry><literal>&gt;</literal></entry><entry>your <link linkend="mbox">$mbox</link> file</entry></row>
<row><entry><literal>&lt;</literal></entry><entry>your <link linkend="record">$record</link> file</entry></row>
<row><entry><literal>^</literal></entry><entry>the current mailbox</entry></row>
<row><entry><literal>-</literal> or <literal>!!</literal></entry><entry>the file you've last visited</entry></row>
<row><entry><literal>~</literal></entry><entry>your home directory</entry></row>
<row><entry><literal>=</literal> or <literal>+</literal></entry><entry>your <link linkend="folder">$folder</link> directory</entry></row>
<row><entry><emphasis>@alias</emphasis></entry><entry>to the <link linkend="save-hook">default save folder</link> as determined by the address of the alias</entry></row>
</tbody>
</tgroup>
</table>

<para>
For example, to store a copy of outgoing messages in the folder they
were composed in, a <link
linkend="folder-hook"><command>folder-hook</command></link> can be used
to set <link linkend="record">$record</link>:
</para>

<screen>
  folder-hook . 'set record=^'
</screen>

<para>
Note: the <link linkend="record">$record</link> shortcut
<quote><literal>&lt;</literal></quote> is substituted without any
regard to multiple mailboxes and <link
linkend="fcc-delimiter">$fcc_delimiter</link>.  If you use multiple
Fcc mailboxes, and also want to use the
<quote><literal>&lt;</literal></quote> mailbox shortcut, it might be
better to set <link linkend="record">$record</link> to the primary
mailbox and use a <link linkend="fcc-hook">fcc-hook</link> to set all
mailboxes during message composition.
</para>

</sect1>

<sect1 id="using-lists">
<title>Handling Mailing Lists</title>

<para>
Mutt has a few configuration options that make dealing with large
amounts of mail easier.  The first thing you must do is to let Mutt know
what addresses you consider to be mailing lists (technically this does
not have to be a mailing list, but that is what it is most often used
for), and what lists you are subscribed to.  This is accomplished
through the use of the <link linkend="lists"><command>lists</command>
and <command>subscribe</command></link> commands in your
<literal>.muttrc</literal>.  Alternatively or additionally, you can set
<link linkend="auto-subscribe">$auto_subscribe</link> to automatically
subscribe addresses found in a <literal>List-Post</literal> header.
</para>

<para>
Now that Mutt knows what your mailing lists are, it can do several
things, the first of which is the ability to show the name of a list
through which you received a message (i.e., of a subscribed list) in the
<emphasis>index</emphasis> menu display.  This is useful to distinguish
between personal and list mail in the same mailbox.  In the <link
linkend="index-format">$index_format</link> variable, the expando
<quote>%L</quote> will print the string <quote>To &lt;list&gt;</quote>
when <quote>list</quote> appears in the <quote>To</quote> field, and
<quote>Cc &lt;list&gt;</quote> when it appears in the <quote>Cc</quote>
field (otherwise it prints the name of the author).
</para>

<para>
Often times the <quote>To</quote> and <quote>Cc</quote> fields in
mailing list messages tend to get quite large. Most people do not bother
to remove the author of the message they reply to from the list,
resulting in two or more copies being sent to that person.  The
<literal>&lt;list-reply&gt;</literal> function, which by default is
bound to <quote>L</quote> in the <emphasis>index</emphasis> menu and
<emphasis>pager</emphasis>, helps reduce the clutter by only replying to
the known mailing list addresses instead of all recipients (except as
specified by <literal>Mail-Followup-To</literal>, see below).
</para>

<para>
Mutt also supports the <literal>Mail-Followup-To</literal> header.  When
you send a message to a list of recipients which includes one or several
known mailing lists, and if the <link
linkend="followup-to">$followup_to</link> option is set, Mutt will
generate a Mail-Followup-To header.  If any of the recipients are
subscribed mailing lists, this header will contain all the recipients
to whom you send this message, but not your address. This indicates that
group-replies or list-replies (also known as <quote>followups</quote>)
to this message should only be sent to the original recipients of the
message, and not separately to you - you'll receive your copy through
one of the mailing lists you are subscribed to.  If none of the
recipients are subscribed mailing lists, the header will also contain
your address, ensuring you receive a copy of replies.
</para>

<para>
Conversely, when group-replying or list-replying to a message which has
a <literal>Mail-Followup-To</literal> header, Mutt will respect this
header if the <link
linkend="honor-followup-to">$honor_followup_to</link> configuration
variable is set.  Using <link linkend="list-reply">list-reply</link>
will in this case also make sure that the reply goes to the mailing
list, even if it's not specified in the list of recipients in the
<literal>Mail-Followup-To</literal>.
</para>

<note>
<para>
When header editing is enabled, you can create a
<literal>Mail-Followup-To</literal> header manually.  Mutt will only
auto-generate this header if it doesn't exist when you send the message.
</para>
</note>

<para>
The other method some mailing list admins use is to generate a
<quote>Reply-To</quote> field which points back to the mailing list
address rather than the author of the message.  This can create problems
when trying to reply directly to the author in private, since most mail
clients will automatically reply to the address given in the
<quote>Reply-To</quote> field.  Mutt uses the <link
linkend="reply-to">$reply_to</link> variable to help decide which
address to use.  If set to <emphasis>ask-yes</emphasis> or
<emphasis>ask-no</emphasis>, you will be prompted as to whether or not
you would like to use the address given in the <quote>Reply-To</quote>
field, or reply directly to the address given in the <quote>From</quote>
field.  When set to <emphasis>yes</emphasis>, the
<quote>Reply-To</quote> field will be used when present.
</para>

<para>
The <quote>X-Label:</quote> header field can be used to further identify
mailing lists or list subject matter (or just to annotate messages
individually).  The <link linkend="index-format">$index_format</link>
variable's <quote>%y</quote> and <quote>%Y</quote> expandos can be used
to expand <quote>X-Label:</quote> fields in the index, and Mutt's
pattern-matcher can match regular expressions to <quote>X-Label:</quote>
fields with the <quote>~y</quote> selector.  <quote>X-Label:</quote> is
not a standard message header field, but it can easily be inserted by
procmail and other mail filtering agents.
</para>

<para>
You can change or delete the <quote>X-Label:</quote> field within
Mutt using the <quote>edit-label</quote> command, bound to the
<quote>y</quote> key by default.  This works for tagged messages, too.
While in the edit-label function, pressing the &lt;complete&gt;
binding (TAB, by default) will perform completion against all labels
currently in use.
</para>

<para>
Lastly, Mutt has the ability to <link linkend="sort">sort</link> the
mailbox into <link linkend="threads">threads</link>.  A thread is a
group of messages which all relate to the same subject.  This is usually
organized into a tree-like structure where a message and all of its
replies are represented graphically.  If you've ever used a threaded
news client, this is the same concept.  It makes dealing with large
volume mailing lists easier because you can easily delete uninteresting
threads and quickly find topics of value.
</para>

</sect1>

<sect1 id="display-munging">
<title>Display Munging</title>

<para>
Working within the confines of a console or terminal window, it is
often useful to be able to modify certain information elements in a
non-destructive way -- to change how they display, without changing
the stored value of the information itself.  This is especially so of
message subjects, which may often be polluted with extraneous metadata
that either is reproduced elsewhere, or is of secondary interest.
</para>

<cmdsynopsis>
<command>subjectrx</command>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">replacement</replaceable>
</arg>

<command>unsubjectrx</command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
<literal>subjectrx</literal> specifies a regular expression
<quote>pattern</quote> which, if detected in a message subject, causes
the subject to be replaced with the <quote>replacement</quote> value.
The replacement is subject to substitutions in the same way as for the
<link linkend="spam">spam</link> command: <literal>%L</literal> for the text
to the left of the match, <literal>%R</literal> for text to the right of the
match, and <literal>%1</literal> for the first subgroup in the match (etc).
If you simply want to erase the match, set it to <quote>%L%R</quote>.
Any number of <literal>subjectrx</literal> commands may coexist.
</para>

<para>
Note this well: the <quote>replacement</quote> value replaces the
entire subject, not just the match!
</para>

<para>
<literal>unsubjectrx</literal> removes a given subjectrx from the
substitution list.  If <literal>*</literal> is used as the pattern,
all substitutions will be removed.
</para>

<example id="ex-subjectrx">
<title>Subject Munging</title>
<screen>
# Erase [rt #12345] tags from Request Tracker (RT) e-mails
subjectrx '\[rt #[0-9]+\] *' '%L%R'

# Servicedesk is another RT that sends more complex subjects.
# Keep the ticket number.
subjectrx '\[servicedesk #([0-9]+)\] ([^.]+)\.([^.]+) - (new|open|pending|update) - ' '%L[#%1] %R'

# Strip out annoying [listname] prefixes in subjects
subjectrx '\[[^]]*\]:? *' '%L%R'
</screen>
</example>

</sect1>

<sect1 id="new-mail">
<title>New Mail Detection</title>

<para>
Mutt supports setups with multiple folders, allowing all of them to be
monitored for new mail (see <xref linkend="mailboxes"/> for details).
</para>

<sect2 id="new-mail-formats">
<title>How New Mail Detection Works</title>

<para>
For Mbox and Mmdf folders, new mail is detected by comparing access
and/or modification times of files: Mutt assumes a folder has new mail
if it wasn't accessed after it was last modified. Utilities like
<literal>biff</literal> or <literal>frm</literal> or any other program
which accesses the mailbox might cause Mutt to never detect new mail for
that mailbox if they do not properly reset the access time. Other
possible causes of Mutt not detecting new mail in these folders are
backup tools (updating access times) or filesystems mounted without
access time update support (for Linux systems, see the
<literal>relatime</literal> option).
</para>

<note>
<para>
Contrary to older Mutt releases, it now maintains the new mail status of
a folder by properly resetting the access time if the folder contains at
least one message which is neither read, nor deleted, nor marked as old.
</para>
</note>

<para>
In cases where new mail detection for Mbox or Mmdf folders appears to be
unreliable, the <link linkend="check-mbox-size">$check_mbox_size</link>
option can be used to make Mutt track and consult file sizes for new
mail detection instead which won't work for size-neutral changes.
</para>

<para>
New mail for Maildir is assumed if there is one message in the
<literal>new/</literal> subdirectory which is not marked deleted (see
<link linkend="maildir-trash">$maildir_trash</link>). For MH folders, a
mailbox is considered having new mail if there's at least one message in
the <quote>unseen</quote> sequence as specified by <link
linkend="mh-seq-unseen">$mh_seq_unseen</link>.
</para>

<para>
Mutt does not poll POP3 folders for new mail, it only periodically
checks the currently opened folder (if it's a POP3 folder).
</para>

<para>
For IMAP, by default Mutt uses recent message counts provided by the
server to detect new mail. If the <link
linkend="imap-idle">$imap_idle</link> option is set, it'll use the IMAP
IDLE extension if advertised by the server.
</para>

<para>
The <link linkend="mail-check-recent">$mail_check_recent</link>
option changes whether Mutt will notify you of new mail in an
already visited mailbox.  When set (the default) it will only notify
you of new mail received since the last time you opened the mailbox.
When unset, Mutt will notify you of any new mail in the mailbox.
</para>

</sect2>

<sect2 id="new-mail-polling">
<title>Polling For New Mail</title>

<para>
When in the index menu and being idle (also see <link
linkend="timeout">$timeout</link>), Mutt periodically checks for new
mail in all folders which have been configured via the
<command>mailboxes</command> command (excepting those specified with
the <literal>-nopoll</literal> flag).  The interval depends on the
folder type: for local/IMAP folders it consults <link
linkend="mail-check">$mail_check</link> and <link
linkend="pop-checkinterval">$pop_checkinterval</link> for POP folders.
</para>

<para>
Outside the index menu the directory browser supports checking for new
mail using the <literal>&lt;check-new&gt;</literal> function which is
unbound by default. Pressing TAB will bring up a menu showing the files
specified by the <command>mailboxes</command> command, and indicate
which contain new messages. Mutt will automatically enter this mode when
invoked from the command line with the <literal>-y</literal> option.
</para>

<para>
For the pager, index and directory browser menus, Mutt contains the
<literal>&lt;buffy-list&gt;</literal> function (bound to
<quote>.</quote> by default) which will print a list of folders with new
mail in the command line at the bottom of the screen.
</para>

<para>
For the index, by default Mutt displays the number of mailboxes with new
mail in the status bar, please refer to the <link
linkend="status-format">$status_format</link> variable for details.
</para>

<para>
When changing folders, Mutt fills the prompt with the first folder from
the mailboxes list containing new mail (if any), pressing
<literal>&lt;Space&gt;</literal> will cycle through folders with new
mail.  The (by default unbound) function
<literal>&lt;next-unread-mailbox&gt;</literal> in the index can be used
to immediately open the next folder with unread mail (if any).
</para>

</sect2>

<sect2 id="new-mail-monitoring">
<title>Monitoring New Mail</title>

<para>
When the <emphasis>Inotify</emphasis> mechanism for monitoring of
files is supported (Linux only) and not disabled at compilation time,
Mutt immediately notifies about new mail for all folders configured
via the <link linkend="mailboxes"><command>mailboxes</command></link>
command (excepting those specified with the <literal>-nopoll</literal>
flag).  Dependent on <link linkend="mailbox-formats">mailbox
format</link> also added <emphasis>old</emphasis> mails are tracked
(not for Maildir).
</para>

<para>
No configuration variables are available.  Trace output is given when
debugging is enabled via <link linkend="tab-commandline-options">command
line option</link> <literal>-d3</literal>.  The lower level 2 only shows
errors, the higher level 5 all including raw Inotify events.
</para>

<note>
<para>
Getting events about new mail is limited to the capabilities of the
underlying mechanism.  <emphasis>Inotify</emphasis> only reports local
changes, i. e. new mail notification works for mails delivered by an
agent on the same machine as Mutt, but not when delivered remotely on
a network file system as NFS.  Also the monitoring handles might fail
in rare conditions, so you better don't completely rely on this
feature.
</para>
</note>

</sect2>

<sect2 id="calc-mailbox-counts">
<title>Calculating Mailbox Message Counts</title>

<para>
If <link linkend="mail-check-stats">$mail_check_stats</link> is set,
Mutt will periodically calculate the unread, flagged, and total
message counts for each mailbox watched by the
<command>mailboxes</command> command.  This calculation takes place at
the same time as new mail polling, but is controlled by a separate
timer: <link
linkend="mail-check-stats-interval">$mail_check_stats_interval</link>.
</para>

<para>
The sidebar can display these message counts.  See <link
linkend="sidebar-format">$sidebar_format</link>.
</para>

</sect2>

</sect1>

<sect1 id="editing-threads">
<title>Editing Threads</title>

<para>
Mutt has the ability to dynamically restructure threads that are broken
either by misconfigured software or bad behavior from some
correspondents. This allows to clean your mailboxes from these
annoyances which make it hard to follow a discussion.
</para>

<sect2 id="link-threads">
<title>Linking Threads</title>

<para>
Some mailers tend to <quote>forget</quote> to correctly set the
<quote>In-Reply-To:</quote> and <quote>References:</quote> headers when
replying to a message. This results in broken discussions because Mutt
has not enough information to guess the correct threading.  You can fix
this by tagging the reply, then moving to the parent message and using
the <literal>&lt;link-threads&gt;</literal> function (bound to &amp; by
default). The reply will then be connected to this parent message.
</para>

<para>
You can also connect multiple children at once, tagging them and using
the <literal>&lt;tag-prefix&gt;</literal> command (<quote>;</quote>) or
the <link linkend="auto-tag">$auto_tag</link> option.
</para>

</sect2>

<sect2 id="break-threads">
<title>Breaking Threads</title>

<para>
On mailing lists, some people are in the bad habit of starting a new
discussion by hitting <quote>reply</quote> to any message from the list
and changing the subject to a totally unrelated one.  You can fix such
threads by using the <literal>&lt;break-thread&gt;</literal> function
(bound by default to #), which will turn the subthread starting from the
current message into a whole different thread.
</para>

</sect2>

</sect1>

<sect1 id="dsn">
<title>Delivery Status Notification (DSN) Support</title>

<para>
RFC1894 defines a set of MIME content types for relaying information
about the status of electronic mail messages.  These can be thought of
as <quote>return receipts.</quote>
</para>

<para>
To support DSN, there are two variables. <link
linkend="dsn-notify">$dsn_notify</link> is used to request receipts for
different results (such as failed message, message delivered, etc.).
<link linkend="dsn-return">$dsn_return</link> requests how much of your
message should be returned with the receipt (headers or full message).
</para>

<para>
When using <link linkend="sendmail">$sendmail</link> for mail delivery,
you need to use either Berkeley sendmail 8.8.x (or greater) a MTA
supporting DSN command line options compatible to Sendmail: The -N and
-R options can be used by the mail client to make requests as to what
type of status messages should be returned. Please consider your MTA
documentation whether DSN is supported.
</para>

<para>
For SMTP delivery using <link linkend="smtp-url">$smtp_url</link>, it
depends on the capabilities announced by the server whether Mutt will
attempt to request DSN or not.
</para>

</sect1>

<sect1 id="urlview">
<title>Start a WWW Browser on URLs</title>

<para>
If a message contains URLs, it is efficient to get a menu with all the
URLs and start a WWW browser on one of them.  This functionality is
provided by the external urlview program which can be retrieved at
<ulink
url="https://github.com/sigpipe/urlview">https://github.com/sigpipe/urlview</ulink>
and the configuration commands:
</para>

<screen>
macro index \cb |urlview\n
macro pager \cb |urlview\n
</screen>

</sect1>

<sect1 id="echo">
<title>Echoing Text</title>

<para>
Usage:
</para>

<cmdsynopsis>
<command>echo</command>
<arg choice="plain">
<replaceable class="parameter">message</replaceable>
</arg>
</cmdsynopsis>

<para>
You can print messages to the message window using the "echo" command.
This might be useful after a macro finishes executing.  After printing
the message, echo will pause for the number of seconds specified by
<link linkend="sleep-time">$sleep_time</link>.
</para>

<screen>
echo "Sourcing muttrc file"

unset confirmappend
macro index ,a "&lt;save-message&gt;=archive&lt;enter&gt;&lt;enter-command&gt;echo 'Saved to archive'&lt;enter&gt;"
</screen>

</sect1>

<sect1 id="compose-flow">
  <title>Message Composition Flow</title>

  <para>
    This is a brief overview of the steps Mutt takes during message
    composition.  It also shows the order and timing of hook execution.
  </para>

  <itemizedlist>
    <listitem>
      <para>
        Reply envelope settings.  <link
        linkend="reverse-name">$reverse_name</link> processing.  To,
        Cc, Subject, References header defaults.
      </para>
    </listitem>
    <listitem>
      <para>
        <link linkend="my-hdr">my_hdr</link> processing for To, Cc,
        Bcc, Subject headers.
      </para>
    </listitem>
    <listitem>
      <para>
        Prompts for To, Cc, Bcc, Subject headers.
        See <link linkend="askcc">$askcc</link>,
        <link linkend="askbcc">$askbcc</link>,
        <link linkend="fast-reply">$fast_reply</link>.
      </para>
    </listitem>
    <listitem>
      <para>
        From header setting.  Note: this is so <link
        linkend="send-hook">send-hook</link>s below can match ~P, but
        From is re-set further below in case a send-hook changes the
        value.
      </para>
    </listitem>
    <listitem>
      <para>
        <link linkend="reply-hook">reply-hook</link>
      </para>
    </listitem>
    <listitem>
      <para>
        <link linkend="send-hook">send-hook</link>
      </para>
    </listitem>
    <listitem>
      <para>
        From header setting.
      </para>
    </listitem>
    <listitem>
      <para>
        <link linkend="my-hdr">my_hdr</link> processing for From,
        Reply-To, Message-ID and user-defined headers.  The To, Cc,
        Bcc, Subject, and Return-Path headers are ignored at this
        stage.
      </para>
    </listitem>
    <listitem>
      <para>
        Message body and signature generation.
      </para>
    </listitem>
    <listitem>
      <para>
        <link linkend="send2-hook">send2-hook</link>
      </para>
    </listitem>
    <listitem>
      <para>
        <link linkend="realname">$realname</link> part of From header setting.
      </para>
    </listitem>
    <listitem>
      <para>
        <link linkend="editor">$editor</link> invocation for the
        message.
      </para>
    </listitem>
    <listitem>
      <para>
        <link linkend="send2-hook">send2-hook</link>
      </para>
    </listitem>
    <listitem>
      <para>
        Cryptographic settings.
      </para>
    </listitem>
    <listitem>
      <para>
        <link linkend="fcc-hook">fcc-hook</link>.  Fcc setting.
      </para>
    </listitem>
    <listitem>
      <para>
        <link linkend="compose-menu">Compose menu</link>.  Note: <link
        linkend="send2-hook">send2-hook</link> is evaluated each time
        the headers are changed.
      </para>
    </listitem>
    <listitem>
      <para>
        Message encryption and signing.  Key selection.
      </para>
    </listitem>
    <listitem>
      <para>
        Fcc saving if <link
        linkend="fcc-before-send">$fcc_before_send</link> is set.  (Note the
        variable documentation for caveats of Fcc'ing before sending.)
      </para>
    </listitem>
    <listitem>
      <para>
        Message sending.
      </para>
    </listitem>
    <listitem>
      <para>
        Fcc saving if <link
        linkend="fcc-before-send">$fcc_before_send</link> is unset
        (the default).  Note: prior to version 1.12, the Fcc was saved
        before sending the message.  It is now by default saved
        afterwards, but if the saving fails, the user is prompted.
      </para>
    </listitem>
  </itemizedlist>
</sect1>

<sect1 id="muttlisp">
  <title>Using MuttLisp (EXPERIMENTAL)</title>
  <para>
    MuttLisp is a Lisp-like enhancement for the Mutt configuration
    file.  It is currently experimental, meaning new releases may
    change or break syntax.  MuttLisp is not a real language, and is
    not meant to be an alternative to macros.  The features are
    purposely minimal, with the actual work still being done by Mutt
    <link linkend="commands">commands</link>.
  </para>
  <para>
    There are two ways to invoke MuttLisp: via the
    <literal>run</literal> command, or interpolated as a command
    argument.
  </para>

  <sect2 id="run">
    <title>Running a command generated by MuttLisp</title>
    <para>
      Usage:
    </para>
    <cmdsynopsis>
      <command>run</command>
      <arg choice="plain">
        <replaceable class="parameter">MuttLisp</replaceable>
      </arg>
    </cmdsynopsis>

    <para>
      The <literal>run</literal> command evaluates the MuttLisp argument.
      The output of the MuttLisp is then executed as a
      Mutt command, as if it were typed in the muttrc instead.
    </para>

<screen>
run (concat "set my_name = '" \
      (or $ENV_NAME "Test User") "'")

  ==> generates and runs the line:
      set my_name = 'Test User'
</screen>

    <para>
      This will set the Mutt <link linkend="set-myvar">User-Defined Variable</link>
      <literal>$my_name</literal> to either the environment variable $ENV_NAME, if
      defined, or else "Test User".
    </para>
  </sect2>

  <sect2 id="muttlisp-interpolate">
    <title>Interpolating MuttLisp in a Command Argument</title>
    <para>
      The second way of running is directly as a command argument.
      An unquoted parenthesis expression will be evaluated, and the result
      substituted as the argument.
    </para>
    <para>
      To avoid breaking existing configurations, this is disabled by
      default.  It can be enabled by setting <link
      linkend="muttlisp-inline-eval">$muttlisp_inline_eval</link>.  Before doing so, you should
      review your Mutt configuration to ensure you don't have any bare
      parenthesis expressions elsewhere, such as the regexp parameter
      of a <link linkend="folder-hook">folder-hook</link>.  These can typically be
      surrounded by single or double-quotes to prevent being evaluated as
      MuttLisp.
    </para>

<screen>
set my_name = (or $ENV_NAME "Test User")
</screen>

    <para>
      The result of the MuttLisp is directly assigned as the argument.
      It isn't reinterpreted, so there is no need for the outer
      quotes.  This is in contrast with the <link
      linkend="run">run</link> command, where the output is
      reinterpreted by the muttrc parser.
    </para>
  </sect2>

  <sect2 id="muttlisp-syntax">
    <title>MuttLisp Syntax</title>
    <para>
      MuttLisp was inspired by Lisp, and so follows the same basic
      syntax.  All statements are surrounded by parenthesis.  The first argument
      inside the parenthesis is a function to invoke.  The remaining arguments
      are passed as parameters.
    </para>
    <para>
      The arguments to functions are read and evaluated using <link
      linkend="muttrc-syntax">muttrc syntax</link>.  This means Mutt
      variables or environment variables can be passed directly, or
      interpolated inside a double-quoted string.
    </para>
    <para>
      Although the arguments to a function are evaluated, the result
      of the function call is not.
    </para>
<screen>
echo (concat '$' 'spoolfile')
  ==> $spoolfile
</screen>

    <para>
      MuttLisp has no types - everything is stored and evaluated as
      a string, just as with the muttrc.  True is defined as a non-empty
      string, and false as the empty string.
    </para>
    <para>
      The muttrc is evaluated line by line, and MuttLisp is similarly
      constrained.  Input can be continued on more than one line by
      placing a backslash at the end of the line.
    </para>
  </sect2>

  <sect2 id="muttlisp-funcs">
    <title>MuttLisp Functions</title>

    <sect3 id="muttlisp-concat">
      <title>concat</title>
      <para>
        Combines all arguments into a single string.
      </para>
<screen>
echo (concat one two three)
  ==> onetwothree
</screen>
    </sect3>

    <sect3 id="muttlisp-quote">
      <title>quote</title>
      <para>
        Prevents interpretation of the list.  Note that the list must
        still obey MuttLisp syntax: single quotes, double quotes,
        backticks, and parenthesis are still parsed prior to
        <literal>quote</literal> running and must be matching.
      </para>
<screen>
echo (quote one two three)
  ==> one two three

echo (quote $spoolfile)
  ==> $spoolfile

echo (quote (one two three))
  ==> (one two three)
</screen>
    </sect3>

    <sect3 id="muttlisp-equal">
      <title>equal</title>
      <para>
        Performs a case-sensitive comparison of each argument.  Stops evaluating
        arguments when it finds the first one that is not equal.  Returns
        "t" if they are all equal, and the empty string if not.
      </para>
<screen>
echo (equal one one)
  ==> "t"

echo (equal one `echo one`)
  ==> "t"

echo (equal one one two `echo three`)
  ==> ""
  note: `echo three` does not execute.

echo (equal "one two" `echo one two`)
  ==> ""
  note: backticks generate two arguments "one" and "two"

echo (equal "one two" "`echo one two`")
  ==> "t"
  note: backticks inside double quotes generates a single argument: "one two"
</screen>
    </sect3>

    <sect3 id="muttlisp-not">
      <title>not</title>
      <para>
        Accepts a single argument only.
        Returns "t" if the argument evaluates to the empty string.
        Otherwise returns the empty string.
      </para>
<screen>
echo (not one)
  ==> ""

echo (not "")
  ==> "t"

echo (not (equal one two))
  ==> "t"
</screen>
    </sect3>

    <sect3 id="muttlisp-and">
      <title>and</title>
      <para>
        Returns the first argument that evalutes to the empty string.
        Otherwise returns the last argument, or "t" if there are no arguments.
      </para>
<screen>
echo (and one two)
  ==> "two"

echo (and "" two `echo three`)
  ==> ""
  note: `echo three` does not execute.

echo (and)
  ==> "t"
</screen>
    </sect3>

    <sect3 id="muttlisp-or">
      <title>or</title>
      <para>
        Returns the first argument that evaluates to a non-empty string.  Otherwise
        returns the empty string.
      </para>
<screen>
echo (or one two)
  ==> "one"

echo (or "" two `echo three`)
  ==> "two"
  note: `echo three` does not execute.

echo (or)
  ==> ""
</screen>
    </sect3>

    <sect3 id="muttlisp-if">
      <title>if</title>
      <para>
        Requires 2 or 3 arguments.  The first is a conditional.  If it
        evaluates to "true" (a non-empty string), the second argument is
        evaluated and returned.  Otherwise the third argument is evaluated
        and returned.
      </para>
<screen>
echo (if a one two)
  ==> "one"

echo (if "" one two)
  ==> "two"

set spoolfile = "/var/mail/user"
echo (if (equal $spoolfile "/var/mail/user") yes no)
  ==> "yes"
</screen>
    </sect3>
  </sect2>

  <sect2 id="muttlisp-examples">
    <title>Examples</title>
    <para>
      It's important to remember that function arguments are
      evaluated, but the result is not.  Also, the result of an
      interpolated command argument is used directly, and needs no
      quoting.
    </para>
<screen>
# A three-way toggle of $index_format:

set muttlisp_inline_eval
set my_idx1 = "one"
set my_idx2 = "two"
set my_idx3 = "three"
set index_format = $my_idx1

macro index i '&lt;enter-command&gt;set index_format =  \
  (or                                             \
    (if (equal $index_format $my_idx1) $my_idx2)  \
    (if (equal $index_format $my_idx2) $my_idx3)  \
    $my_idx1) \
&lt;enter&gt;'
</screen>

    <para>
      The output of the run command is re-evaluated by the muttrc
      parser.  So it's important to pay more attention to quoting
      issues when generating the command string below.
    </para>
<screen>
# Conditionally set up background editing in tmux or GNU Screen:

run \
  (if (or $STY $TMUX)                             \
    (concat                                       \
      'set background_edit;'                      \
      'set editor = "bgedit-screen-tmux.sh vim"') \
    (concat                                       \
      'unset background_edit;'                    \
      'set editor = "vim"'))
</screen>

  <para>
    Because backticks are evaluated by MuttLisp too, we need to use
    the run command below and pay close attention to quoting.
  </para>
<screen>
# Use a Mutt variable inside backticks.

set spoolfile = "/var/mail/testuser"

# This will generate and then run the command string:
#   set my_var = "`~/bin/myscript.sh /var/mail/testuser`"
run                                       \
  (concat                                 \
     'set my_var = "`~/bin/myscript.sh '  \
     $spoolfile                           \
     '`"')
</screen>
  </sect2>

</sect1>

<sect1 id="misc-topics">
<title>Miscellany</title>

<para>
This section documents various features that fit nowhere else.
</para>

<variablelist>
<varlistentry>
<term>
Address normalization
</term>
<listitem>
<para>
Mutt normalizes all e-mail addresses to the simplest form possible. If
an address contains a realname, the form <emphasis>Joe User
&lt;joe@example.com&gt;</emphasis> is used and the pure e-mail address
without angle brackets otherwise, i.e. just
<emphasis>joe@example.com</emphasis>.
</para>
<para>
This normalization affects all headers Mutt generates including aliases.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
Initial folder selection
</term>
<listitem>
<para>
The folder Mutt opens at startup is determined as follows: the folder
specified in the <literal>$MAIL</literal> environment variable if
present. Otherwise, the value of <literal>$MAILDIR</literal> is taken
into account. If that isn't present either, Mutt takes the user's
mailbox in the mailspool as determined at compile-time (which may also
reside in the home directory). The <link
linkend="spoolfile">$spoolfile</link> setting overrides this
selection. Highest priority has the mailbox given with the
<literal>-f</literal> command line option.
</para>
</listitem>
</varlistentry>
</variablelist>

</sect1>

</chapter>

<chapter id="mimesupport">
<title>Mutt's MIME Support</title>

<para>
Quite a bit of effort has been made to make Mutt the premier text-mode
MIME MUA.  Every effort has been made to provide the functionality that
the discerning MIME user requires, and the conformance to the standards
wherever possible.  When configuring Mutt for MIME, there are two extra
types of configuration files which Mutt uses.  One is the
<literal>mime.types</literal> file, which contains the mapping of file
extensions to IANA MIME types.  The other is the
<literal>mailcap</literal> file, which specifies the external commands
to use for handling specific MIME types.
</para>

<sect1 id="using-mime">
<title>Using MIME in Mutt</title>

<sect2 id="mime-overview">
<title>MIME Overview</title>

<para>
MIME is short for <quote>Multipurpose Internet Mail Extension</quote>
and describes mechanisms to internationalize and structure mail
messages. Before the introduction of MIME, messages had a single text
part and were limited to us-ascii header and content. With MIME,
messages can have attachments (and even attachments which itself have
attachments and thus form a tree structure), nearly arbitrary characters
can be used for sender names, recipients and subjects.
</para>

<para>
Besides the handling of non-ascii characters in message headers, to Mutt
the most important aspect of MIME are so-called MIME types. These are
constructed using a <emphasis>major</emphasis> and
<emphasis>minor</emphasis> type separated by a forward slash.  These
specify details about the content that follows. Based upon these, Mutt
decides how to handle this part. The most popular major type is
<quote><literal>text</literal></quote> with minor types for plain text,
HTML and various other formats. Major types also exist for images,
audio, video and of course general application data (e.g. to separate
cryptographically signed data with a signature, send office documents,
and in general arbitrary binary data). There's also the
<literal>multipart</literal> major type which represents the root of a
subtree of MIME parts. A list of supported MIME types can be found in
<xref linkend="supported-mime-types"/>.
</para>

<para>
MIME also defines a set of encoding schemes for transporting MIME
content over the network: <literal>7bit</literal>,
<literal>8bit</literal>, <literal>quoted-printable</literal>,
<literal>base64</literal> and <literal>binary</literal>. There're some
rules when to choose what for encoding headers and/or body (if needed),
and Mutt will in general make a good choice.
</para>

<para>
Mutt does most of MIME encoding/decoding behind the scenes to form
messages conforming to MIME on the sending side. On reception, it can be
flexibly configured as to how what MIME structure is displayed (and if
it's displayed): these decisions are based on the content's MIME type.
There are three areas/menus in dealing with MIME: the pager (while
viewing a message), the attachment menu and the compose menu.
</para>

</sect2>

<sect2 id="mime-pager">
<title>Viewing MIME Messages in the Pager</title>

<para>
When you select a message from the index and view it in the pager, Mutt
decodes as much of a message as possible to a text representation.  Mutt
internally supports a number of MIME types, including the
<literal>text</literal> major type (with all minor types), the
<literal>message/rfc822</literal> (mail messages) type and some
<literal>multipart</literal> types. In addition, it recognizes a variety
of PGP MIME types, including PGP/MIME and
<literal>application/pgp</literal>.
</para>

<para>
Mutt will denote attachments with a couple lines describing them.
These lines are of the form:
</para>

<screen>
[-- Attachment #1: Description --]
[-- Type: text/plain, Encoding: 7bit, Size: 10000 --]
</screen>

<para>
Where the <emphasis>Description</emphasis> is the description or
filename given for the attachment, and the <emphasis>Encoding</emphasis>
is one of the already mentioned content encodings.
</para>

<para>
If Mutt cannot deal with a MIME type, it will display a message like:
</para>

<screen>
[-- image/gif is unsupported (use 'v' to view this part) --]
</screen>

</sect2>

<sect2 id="attach-menu">
<title>The Attachment Menu</title>

<para>
The default binding for <literal>&lt;view-attachments&gt;</literal> is
<quote>v</quote>, which displays the attachment menu for a message.  The
attachment menu displays a list of the attachments in a message.  From
the attachment menu, you can save, print, pipe, delete, and view
attachments.  You can apply these operations to a group of attachments
at once, by tagging the attachments and by using the
<literal>&lt;tag-prefix&gt;</literal> operator.  You can also reply to
the current message from this menu, and only the current attachment (or
the attachments tagged) will be quoted in your reply.  You can view
attachments as text, or view them using the mailcap viewer definition
(the mailcap mechanism is explained later in detail).
</para>

<para>
Finally, you can apply the usual message-related functions (like <link
linkend="resend-message"><literal>&lt;resend-message&gt;</literal></link>,
and the <literal>&lt;reply&gt;</literal> and
<literal>&lt;forward&gt;</literal> functions) to attachments of type
<literal>message/rfc822</literal>.
</para>

<para>
See table <xref linkend="tab-attachment-bindings"/> for all available
functions.
</para>

</sect2>

<sect2 id="compose-menu">
<title>The Compose Menu</title>

<para>
The compose menu is the menu you see before you send a message.  It
allows you to edit the recipient list, the subject, and other aspects of
your message.  It also contains a list of the attachments of your
message, including the main body.  From this menu, you can print, copy,
filter, pipe, edit, compose, review, and rename an attachment or a list
of tagged attachments.  You can also modifying the attachment
information, notably the type, encoding and description.
</para>

<para>
Attachments appear as follows by default:
</para>

<screen>
- 1 [text/plain, 7bit, 1K]           /tmp/mutt-euler-8082-0 &lt;no description&gt;
  2 [applica/x-gunzip, base64, 422K] ~/src/mutt-0.85.tar.gz &lt;no description&gt;
</screen>

<para>
The <quote>-</quote> denotes that Mutt will delete the file after
sending (or postponing, or canceling) the message.  It can be toggled
with the <literal>&lt;toggle-unlink&gt;</literal> command (default: u).
The next field is the MIME content-type, and can be changed with the
<literal>&lt;edit-type&gt;</literal> command (default: ^T).  The next
field is the encoding for the attachment, which allows a binary message
to be encoded for transmission on 7bit links.  It can be changed with
the <literal>&lt;edit-encoding&gt;</literal> command (default: ^E).  The
next field is the size of the attachment, rounded to kilobytes or
megabytes.  The next field is the filename, which can be changed with
the <literal>&lt;rename-file&gt;</literal> command (default: R).  The
final field is the description of the attachment, and can be changed
with the <literal>&lt;edit-description&gt;</literal> command (default:
d). See <link linkend="attach-format">$attach_format</link> for a full
list of available expandos to format this display to your needs.
</para>

</sect2>

</sect1>

<sect1 id="mime-types">
<title>MIME Type Configuration with <literal>mime.types</literal></title>

<para>
To get most out of MIME, it's important that a MIME part's content type
matches the content as closely as possible so that the recipient's
client can automatically select the right viewer for the
content. However, there's no reliable for Mutt to know how to detect
every possible file type. Instead, it uses a simple plain text mapping
file that specifies what file extension corresponds to what MIME
type. This file is called <literal>mime.types</literal>.
</para>

<para>
When you add an attachment to your mail message, Mutt searches your
personal <literal>mime.types</literal> file at
<literal>$HOME/.mime.types</literal>, and then the system
<literal>mime.types</literal> file at
<literal>/usr/local/share/mutt/mime.types</literal> or
<literal>/etc/mime.types</literal>
</para>

<para>
Each line starts with the full MIME type, followed by a space and
space-separated list of file extensions. For example you could use:
</para>

<example id="ex-mime-types">
<title><literal>mime.types</literal></title>
<screen>
application/postscript          ps eps
application/pgp                 pgp
audio/x-aiff                    aif aifc aiff
</screen>
</example>

<para>
A sample <literal>mime.types</literal> file comes with the Mutt
distribution, and should contain most of the MIME types you are likely
to use.
</para>

<para>
If Mutt can not determine the MIME type by the extension of the file you
attach, it will run the command specified in
<link linkend="mime-type-query-command">$mime_type_query_command</link>.
If that command is not specified, Mutt will look at the file.  If the file
is free of binary information, Mutt will assume that the file is plain text,
and mark it as <literal>text/plain</literal>.  If the file contains binary
information, then Mutt will mark it as
<literal>application/octet-stream</literal>.  You can change the MIME
type that Mutt assigns to an attachment by using the
<literal>&lt;edit-type&gt;</literal> command from the compose menu
(default: ^T), see <xref linkend="supported-mime-types"/> for supported
major types. Mutt recognizes all of these if the appropriate entry is
found in the <literal>mime.types</literal> file. Non-recognized mime
types should only be used if the recipient of the message is likely to
be expecting such attachments.
</para>

<table id="supported-mime-types">
<title>Supported MIME types</title>
<tgroup cols="3">
<thead>
<row><entry>MIME major type</entry><entry>Standard</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry><literal>application</literal></entry><entry>yes</entry><entry>General application data</entry></row>
<row><entry><literal>audio</literal></entry><entry>yes</entry><entry>Audio data</entry></row>
<row><entry><literal>image</literal></entry><entry>yes</entry><entry>Image data</entry></row>
<row><entry><literal>message</literal></entry><entry>yes</entry><entry>Mail messages, message status information</entry></row>
<row><entry><literal>model</literal></entry><entry>yes</entry><entry>VRML and other modeling data</entry></row>
<row><entry><literal>multipart</literal></entry><entry>yes</entry><entry>Container for other MIME parts</entry></row>
<row><entry><literal>text</literal></entry><entry>yes</entry><entry>Text data</entry></row>
<row><entry><literal>video</literal></entry><entry>yes</entry><entry>Video data</entry></row>
<row><entry><literal>chemical</literal></entry><entry>no</entry><entry>Mostly molecular data</entry></row>
</tbody>
</tgroup>
</table>

<para>
MIME types are not arbitrary, they need to be assigned by <ulink
url="http://www.iana.org/assignments/media-types/">IANA</ulink>.
</para>

</sect1>

<sect1 id="mailcap">
<title>MIME Viewer Configuration with Mailcap</title>

<para>
Mutt supports RFC 1524 MIME Configuration, in particular the Unix
specific format specified in Appendix A of RFC 1524.  This file format
is commonly referred to as the <quote>mailcap</quote> format.  Many MIME
compliant programs utilize the mailcap format, allowing you to specify
handling for all MIME types in one place for all programs.  Programs
known to use this format include Firefox, lynx and metamail.
</para>

<para>
In order to handle various MIME types that Mutt doesn't have built-in
support for, it parses a series of external configuration files to find
an external handler. The default search string for these files is a
colon delimited list containing the following files:
</para>

<orderedlist>
<listitem><para><literal>$HOME/.mailcap</literal></para></listitem>
<listitem><para><literal>$PKGDATADIR/mailcap</literal></para></listitem>
<listitem><para><literal>$SYSCONFDIR/mailcap</literal></para></listitem>
<listitem><para><literal>/etc/mailcap</literal></para></listitem>
<listitem><para><literal>/usr/etc/mailcap</literal></para></listitem>
<listitem><para><literal>/usr/local/etc/mailcap</literal></para></listitem>
</orderedlist>

<para>
where <literal>$HOME</literal> is your home directory. The
<literal>$PKGDATADIR</literal> and the <literal>$SYSCONFDIR</literal>
directories depend on where Mutt is installed: the former is the default
for shared data, the latter for system configuration files.
</para>

<para>
The default search path can be obtained by running the following
command:
</para>

<screen>
mutt -nF /dev/null -Q mailcap_path
</screen>

<para>
In particular, the metamail distribution will install a mailcap file,
usually as <literal>/usr/local/etc/mailcap</literal>, which contains
some baseline entries.
</para>

<sect2 id="mailcap-basics">
<title>The Basics of the Mailcap File</title>

<para>
A mailcap file consists of a series of lines which are comments, blank,
or definitions.
</para>

<para>
A comment line consists of a # character followed by anything you want.
</para>

<para>
A blank line is blank.
</para>

<para>
A definition line consists of a content type, a view command, and any
number of optional fields.  Each field of a definition line is divided
by a semicolon <quote>;</quote> character.
</para>

<para>
The content type is specified in the MIME standard
<quote>type/subtype</quote> notation.  For example,
<literal>text/plain</literal>, <literal>text/html</literal>,
<literal>image/gif</literal>, etc.  In addition, the mailcap format
includes two formats for wildcards, one using the special
<quote>*</quote> subtype, the other is the implicit wild, where you only
include the major type.  For example, <literal>image/*</literal>, or
<literal>video</literal> will match all image types and video types,
respectively.
</para>

<para>
The view command is a Unix command for viewing the type specified. There
are two different types of commands supported. The default is to send
the body of the MIME message to the command on stdin. You can change
this behavior by using <literal>%s</literal> as a parameter to your view
command.  This will cause Mutt to save the body of the MIME message to a
temporary file, and then call the view command with the
<literal>%s</literal> replaced by the name of the temporary file. In
both cases, Mutt will turn over the terminal to the view program until
the program quits, at which time Mutt will remove the temporary file if
it exists. This means that mailcap does <emphasis>not</emphasis> work
out of the box with programs which detach themselves from the terminal
right after starting, like <literal>open</literal> on Mac OS X. In order
to nevertheless use these programs with mailcap, you probably need
custom shell scripts.
</para>

<para>
So, in the simplest form, you can send a <literal>text/plain</literal>
message to the external pager more on standard input:
</para>

<screen>
text/plain; more
</screen>

<para>
Or, you could send the message as a file:
</para>

<screen>
text/plain; more %s
</screen>

<para>
Perhaps you would like to use lynx to interactively view a
<literal>text/html</literal> message:
</para>

<screen>
text/html; lynx %s
</screen>

<para>
In this case, lynx does not support viewing a file from standard input,
so you must use the <literal>%s</literal> syntax.
</para>

<note>
<para>
<emphasis>Some older versions of lynx contain a bug where they will
check the mailcap file for a viewer for <literal>text/html</literal>.
They will find the line which calls lynx, and run it.  This causes lynx
to continuously spawn itself to view the object.</emphasis>
</para>
</note>

<para>
On the other hand, maybe you don't want to use lynx interactively, you
just want to have it convert the <literal>text/html</literal> to
<literal>text/plain</literal>, then you can use:
</para>

<screen>
text/html; lynx -dump %s | more
</screen>

<para>
Perhaps you wish to use lynx to view <literal>text/html</literal> files,
and a pager on all other text formats, then you would use the following:
</para>

<screen>
text/html; lynx %s
text/*; more
</screen>

</sect2>

<sect2 id="secure-mailcap">
<title>Secure Use of Mailcap</title>

<para>
The interpretation of shell meta-characters embedded in MIME parameters
can lead to security problems in general.  Mutt tries to quote
parameters in expansion of <literal>%s</literal> syntaxes properly, and
avoids risky characters by substituting them, see the <link
linkend="mailcap-sanitize">$mailcap_sanitize</link> variable.
</para>

<para>
Although Mutt's procedures to invoke programs with mailcap seem to be
safe, there are other applications parsing mailcap, maybe taking less
care of it.  Therefore you should pay attention to the following rules:
</para>

<para>
<emphasis>Keep the %-expandos away from shell quoting.</emphasis> Don't
quote them with single or double quotes.  Mutt does this for you, the
right way, as should any other program which interprets mailcap.  Don't
put them into backtick expansions.  Be highly careful with evil
statements, and avoid them if possible at all.  Trying to fix broken
behavior with quotes introduces new leaks &mdash; there is no
alternative to correct quoting in the first place.
</para>

<para>
If you have to use the %-expandos' values in context where you need
quoting or backtick expansions, put that value into a shell variable and
reference the shell variable where necessary, as in the following
example (using <literal>$charset</literal> inside the backtick expansion
is safe, since it is not itself subject to any further expansion):
</para>

<screen>
text/test-mailcap-bug; cat %s; copiousoutput; test=charset=%{charset} \
        &amp;&amp; test "`echo $charset | tr '[A-Z]' '[a-z]'`" != iso-8859-1
</screen>

</sect2>

<sect2 id="advanced-mailcap">
<title>Advanced Mailcap Usage</title>

<sect3 id="optional-mailcap-fields">
<title>Optional Fields</title>

<para>
In addition to the required content-type and view command fields, you
can add semi-colon <quote>;</quote> separated fields to set flags and
other options.  Mutt recognizes the following optional fields:
</para>

<variablelist>

<varlistentry>
<term>copiousoutput</term>
<listitem>
<para>
This flag tells Mutt that the command passes possibly large amounts of
text on standard output.  This causes Mutt to invoke a pager (either
the internal pager or the external pager defined by the pager variable)
on the output of the view command.  Without this flag, Mutt assumes that
the command is interactive.  One could use this to replace the pipe to
<literal>more</literal> in the <literal>lynx -dump</literal> example in
the Basic section:
</para>

<screen>
text/html; lynx -dump %s ; copiousoutput
</screen>

<para>
This will cause lynx to format the <literal>text/html</literal> output
as <literal>text/plain</literal> and Mutt will use your standard pager
to display the results.
</para>

<para>
Mutt will set the <literal>COLUMNS</literal> environment variable to
the width of the pager.  Some programs make use of this environment
variable automatically.  Others provide a command line argument that
can use this to set the output width:
</para>

<screen>
text/html; lynx -dump -width ${COLUMNS:-80} %s; copiousoutput
</screen>

<para>
Note that when using the built-in pager, <emphasis>only</emphasis>
entries with this flag will be considered a handler for a MIME type
&mdash; all other entries will be ignored.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>needsterminal</term>
<listitem>
<para>
Mutt uses this flag when viewing attachments with <link
linkend="auto-view"><command>auto_view</command></link>, in order to
decide whether it should honor the setting of the <link
linkend="wait-key">$wait_key</link> variable or not.  When an attachment
is viewed using an interactive program, and the corresponding mailcap
entry has a <emphasis>needsterminal</emphasis> flag, Mutt will use <link
linkend="wait-key">$wait_key</link> and the exit status of the program
to decide if it will ask you to press a key after the external program
has exited.  In all other situations it will not prompt you for a key.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>compose=&lt;command&gt;</term>
<listitem>
<para>
This flag specifies the command to use to create a new attachment of a
specific MIME type.  Mutt supports this from the compose menu.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>composetyped=&lt;command&gt;</term>
<listitem>
<para>
This flag specifies the command to use to create a new attachment of a
specific MIME type.  This command differs from the compose command in
that Mutt will expect standard MIME headers on the data.  This can be
used to specify parameters, filename, description, etc. for a new
attachment.  Mutt supports this from the compose menu.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>print=&lt;command&gt;</term>
<listitem>
<para>
This flag specifies the command to use to print a specific MIME type.
Mutt supports this from the attachment and compose menus.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>edit=&lt;command&gt;</term>
<listitem>
<para>
This flag specifies the command to use to edit a specific MIME type.
Mutt supports this from the compose menu, and also uses it to compose
new attachments.  Mutt will default to the defined <link
linkend="editor">$editor</link> for text attachments.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>nametemplate=&lt;template&gt;</term>
<listitem>
<para>
This field specifies the format for the file denoted by
<literal>%s</literal> in the command fields.  Certain programs will
require a certain file extension, for instance, to correctly view a
file.  For instance, lynx will only interpret a file as
<literal>text/html</literal> if the file ends in
<literal>.html</literal>.  So, you would specify lynx as a
<literal>text/html</literal> viewer with a line in the mailcap file
like:
</para>

<screen>
text/html; lynx %s; nametemplate=%s.html
</screen>

</listitem>
</varlistentry>
<varlistentry>
<term>test=&lt;command&gt;</term>
<listitem>
<para>
This field specifies a command to run to test whether this mailcap entry
should be used.  The command is defined with the command expansion rules
defined in the next section.  If the command returns 0, then the test
passed, and Mutt uses this entry.  If the command returns non-zero, then
the test failed, and Mutt continues searching for the right entry.  Note
that the content-type must match before Mutt performs the test.  For
example:
</para>

<screen>
text/html; firefox -remote 'openURL(%s)' ; test=RunningX
text/html; lynx %s
</screen>

<para>
In this example, Mutt will run the program <literal>RunningX</literal>
which will return 0 if the X Window manager is running, and non-zero if
it isn't.  If <literal>RunningX</literal> returns 0, then Mutt will run
firefox to display the <literal>text/html</literal> object.  If RunningX
doesn't return 0, then Mutt will go on to the next entry and use lynx to
display the <literal>text/html</literal> object.
</para>
</listitem>
</varlistentry>
</variablelist>

</sect3>

<sect3 id="mailcap-search-order">
<title>Search Order</title>

<para>
When searching for an entry in the mailcap file, Mutt will search for
the most useful entry for its purpose.  For instance, if you are
attempting to print an <literal>image/gif</literal>, and you have the
following entries in your mailcap file, Mutt will search for an entry
with the print command:
</para>

<screen>
image/*;        xv %s
image/gif;      ; print= anytopnm %s | pnmtops | lpr; \
                nametemplate=%s.gif
</screen>

<para>
Mutt will skip the <literal>image/*</literal> entry and use the
<literal>image/gif</literal> entry with the print command.
</para>

<para>
In addition, you can use this with <link
linkend="auto-view"><command>auto_view</command></link> to denote two
commands for viewing an attachment, one to be viewed automatically, the
other to be viewed interactively from the attachment menu using the
<literal>&lt;view-mailcap&gt;</literal> function (bound to
<quote>m</quote> by default). In addition, you can then use the test
feature to determine which viewer to use interactively depending on your
environment.
</para>

<screen>
text/html;      firefox -remote 'openURL(%s)' ; test=RunningX
text/html;      lynx %s; nametemplate=%s.html
text/html;      lynx -dump %s; nametemplate=%s.html; copiousoutput
</screen>

<para>
For <link linkend="auto-view"><command>auto_view</command></link>, Mutt
will choose the third entry because of the
<literal>copiousoutput</literal> tag.  For interactive viewing, Mutt
will run the program <literal>RunningX</literal> to determine if it
should use the first entry.  If the program returns non-zero, Mutt will
use the second entry for interactive viewing. The last entry is for
inline display in the pager and the
<literal>&lt;view-attach&gt;</literal> function in the attachment menu.
</para>

<para>
Entries with the <literal>copiousoutput</literal> tag should always be
specified as the last one per type. For non-interactive use, the last
entry will then actually be the first matching one with the tag set.
For non-interactive use, only <literal>copiousoutput</literal>-tagged
entries are considered. For interactive use, Mutt ignores this tag and
treats all entries equally. Therefore, if not specified last, all
following entries without this tag would never be considered for
<literal>&lt;view-attach&gt;</literal> because the
<literal>copiousoutput</literal> before them matched already.
</para>

</sect3>

<sect3 id="mailcap-command-expansion">
<title>Command Expansion</title>

<para>
The various commands defined in the mailcap files are passed to the
<literal>/bin/sh</literal> shell using the <literal>system(3)</literal>
function.  Before the command is passed to <literal>/bin/sh
-c</literal>, it is parsed to expand various special parameters with
information from Mutt.  The keywords Mutt expands are:
</para>

<variablelist>

<varlistentry>
<term>%s</term>
<listitem>
<para>
As seen in the basic mailcap section, this variable is expanded to a
filename specified by the calling program.  This file contains the body
of the message to view/print/edit or where the composing program should
place the results of composition.  In addition, the use of this keyword
causes Mutt to not pass the body of the message to the view/print/edit
program on stdin.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>%t</term>
<listitem>
<para>
Mutt will expand <literal>%t</literal> to the text representation of the
content type of the message in the same form as the first parameter of
the mailcap definition line, i.e. <literal>text/html</literal> or
<literal>image/gif</literal>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>%{&lt;parameter&gt;}</term>
<listitem>
<para>
Mutt will expand this to the value of the specified parameter from the
Content-Type: line of the mail message.  For instance, if your mail
message contains:
</para>

<screen>
Content-Type: text/plain; charset=iso-8859-1
</screen>

<para>
then Mutt will expand <literal>%{charset}</literal> to
<quote>iso-8859-1</quote>.  The default metamail mailcap file uses this
feature to test the charset to spawn an xterm using the right charset to
view the message.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>\%</term>
<listitem>
<para>
This will be replaced by a literal <literal>%</literal>.
</para>
</listitem>
</varlistentry>
</variablelist>

<para>
Mutt does not currently support the <literal>%F</literal> and
<literal>%n</literal> keywords specified in RFC 1524.  The main purpose
of these parameters is for multipart messages, which is handled
internally by Mutt.
</para>

</sect3>

</sect2>

<sect2 id="mailcap-example">
<title>Example Mailcap Files</title>

<para>
This mailcap file is fairly simple and standard:
</para>

<screen>
<emphasis role="comment"># I'm always running X :)</emphasis>
video/*;        xanim %s &gt; /dev/null
image/*;        xv %s &gt; /dev/null

<emphasis role="comment"># I'm always running firefox (if my computer had more memory, maybe)</emphasis>
text/html;      firefox -remote 'openURL(%s)'
</screen>

<para>
This mailcap file shows quite a number of examples:
</para>

<screen>
<emphasis role="comment"># Use xanim to view all videos   Xanim produces a header on startup,
# send that to /dev/null so I don't see it</emphasis>
video/*;        xanim %s &gt; /dev/null

<emphasis role="comment"># Send html to a running firefox by remote</emphasis>
text/html;      firefox -remote 'openURL(%s)'; test=RunningFirefox

<emphasis role="comment"># If I'm not running firefox but I am running X, start firefox on the
# object</emphasis>
text/html;      firefox %s; test=RunningX

<emphasis role="comment"># Else use lynx to view it as text</emphasis>
text/html;      lynx %s

<emphasis role="comment"># This version would convert the text/html to text/plain</emphasis>
text/html;      lynx -dump %s; copiousoutput

<emphasis role="comment"># I use enscript to print text in two columns to a page</emphasis>
text/*;         more %s; print=enscript -2Gr %s

<emphasis role="comment"># Firefox adds a flag to tell itself to view jpegs internally</emphasis>
image/jpeg;xv %s; x-mozilla-flags=internal

<emphasis role="comment"># Use xv to view images if I'm running X</emphasis>
<emphasis role="comment"># In addition, this uses the \ to extend the line and set my editor</emphasis>
<emphasis role="comment"># for images</emphasis>
image/*;xv %s; test=RunningX; \
        edit=xpaint %s

<emphasis role="comment"># Convert images to text using the netpbm tools</emphasis>
image/*;  (anytopnm %s | pnmscale -xysize 80 46 | ppmtopgm | pgmtopbm |
pbmtoascii -1x2 ) 2&gt;&amp;1 ; copiousoutput

<emphasis role="comment"># Send excel spreadsheets to my NT box</emphasis>
application/ms-excel; open.pl %s
</screen>

</sect2>

</sect1>

<sect1 id="auto-view">
<title>MIME Autoview</title>

<para>
Usage:
</para>

<cmdsynopsis>
<command>auto_view</command>
<arg choice="plain">
<replaceable>mimetype</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable>mimetype</replaceable>
</arg>

<command>unauto_view</command>
<group choice="req">
<arg choice="plain">
<replaceable>*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable>mimetype</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
In addition to explicitly telling Mutt to view an attachment with the
MIME viewer defined in the mailcap file from the attachments menu, Mutt
has support for automatically viewing MIME attachments while in the
pager.
</para>

<para>
For this to work, you must define a viewer in the mailcap file which
uses the <literal>copiousoutput</literal> option to denote that it is
non-interactive.  Usually, you also use the entry to convert the
attachment to a text representation which you can view in the pager.
</para>

<para>
You then use the <command>auto_view</command> configuration command to
list the content-types that you wish to view automatically.  For
instance, if you set it to:
</para>

<screen>
auto_view text/html application/x-gunzip \
  application/postscript image/gif application/x-tar-gz
</screen>

<para>
...Mutt would try to find corresponding entries for rendering
attachments of these types as text. A corresponding mailcap could look
like:
</para>

<screen>
text/html;      lynx -dump %s; copiousoutput; nametemplate=%s.html
image/*;        anytopnm %s | pnmscale -xsize 80 -ysize 50 | ppmtopgm | \
                pgmtopbm | pbmtoascii ; copiousoutput
application/x-gunzip;   gzcat; copiousoutput
application/x-tar-gz; gunzip -c %s | tar -tf - ; copiousoutput
application/postscript; ps2ascii %s; copiousoutput
</screen>

<para>
<command>unauto_view</command> can be used to remove previous entries
from the <command>auto_view</command> list.  This can be used with <link
linkend="message-hook"><command>message-hook</command></link> to
autoview messages based on size, etc.
<quote><command>unauto_view</command> *</quote> will remove all previous
entries.
</para>

</sect1>

<sect1 id="alternative-order">
<title>MIME Multipart/Alternative</title>

<para>
The <literal>multipart/alternative</literal> container type only has
child MIME parts which represent the same content in an alternative
way. This is often used to send HTML messages which contain an
alternative plain text representation.
</para>

<para>
Mutt has some heuristics for determining which attachment of a
<literal>multipart/alternative</literal> type to display:
</para>

<orderedlist>
<listitem>
<para>
First, Mutt will check the <command>alternative_order</command> list to
determine if one of the available types is preferred.  It consists of a
number of MIME types in order, including support for implicit and
explicit wildcards. For example:
</para>

<screen>
alternative_order text/enriched text/plain text \
  application/postscript image/*
</screen>
</listitem>
<listitem>
<para>
Next, Mutt will check if any of the types have a defined <link
linkend="auto-view"><command>auto_view</command></link>, and use that.
</para>
</listitem>
<listitem>
<para>
Failing that, Mutt will look for any text type.
</para>
</listitem>
<listitem>
<para>
As a last attempt, Mutt will look for any type it knows how to handle.
</para>
</listitem>
</orderedlist>

<para>
To remove a MIME type from the <command>alternative_order</command>
list, use the <command>unalternative_order</command> command.
</para>

<para>
Generating <literal>multipart/alternative</literal> content is supported
via the
<link linkend="send-multipart-alternative">$send_multipart_alternative</link>
quadoption and
<link linkend="send-multipart-alternative-filter">$send_multipart_alternative_filter</link>
filter script.  The composed <literal>text/plain</literal> content
will be piped to the filter script's stdin.  The output from the
filter script should be the generated mime type of the content, a
blank line, and the content.  For example:
</para>
<screen>
text/html

&lt;html&gt;
&lt;body&gt;
Content in html format
&lt;/body&gt;
&lt;/html&gt;
</screen>

<para>
A preview of the alternative can be viewed in the compose menu using the functions
<literal>&lt;view-alt&gt;</literal>,
<literal>&lt;view-alt-text&gt;</literal> and
<literal>&lt;view-alt-mailcap&gt;</literal>, bound to
&quot;v&quot;, &quot;Esc v&quot; and &quot;V&quot; by default.
</para>

</sect1>

<sect1 id="attachments">
<title>Attachment Searching and Counting</title>

<para>
If you ever lose track of attachments in your mailboxes, Mutt's
attachment-counting and -searching support might be for you.  You can
make your message index display the number of qualifying attachments in
each message, or search for messages by attachment count.  You also can
configure what kinds of attachments qualify for this feature with the
<command>attachments</command> and <command>unattachments</command>
commands.
</para>

<para>
In order to provide this information, Mutt needs to fully MIME-parse all
messages affected first. This can slow down operation especially for
remote mail folders such as IMAP because all messages have to be
downloaded first regardless whether the user really wants to view them
or not though using <xref linkend="body-caching"/> usually means to
download the message just once.
</para>

<para>
By default, Mutt will not search inside
<literal>multipart/alternative</literal> containers.  This can be
changed via the <link
linkend="count-alternatives">$count_alternatives</link> configuration
variable.
</para>

<para>
The syntax is:
</para>

<cmdsynopsis>
<command>attachments</command>
<arg choice="plain">
<replaceable>{ + | - }disposition</replaceable>
</arg>
<arg choice="plain">
<replaceable>mime-type</replaceable>
</arg>

<command>unattachments</command>
<arg choice="plain">
<replaceable>{ + | - }disposition</replaceable>
</arg>
<arg choice="plain">
<replaceable>mime-type</replaceable>
</arg>

<command>attachments</command>
<arg choice="plain">
<option>?</option>
</arg>

<command>unattachments</command>
<arg choice="plain">
<option>*</option>
</arg>
</cmdsynopsis>

<para>
<emphasis>disposition</emphasis> is the attachment's Content-Disposition
type &mdash; either <literal>inline</literal> or
<literal>attachment</literal>.  You can abbreviate this to
<literal>I</literal> or <literal>A</literal>.
</para>

<para>
The first part of a message or multipart group, if inline, is counted
separately than other inline parts.  Specify <literal>root</literal>
or <literal>R</literal> for <emphasis>disposition</emphasis> to count
these as attachments.  If this first part is of type
multipart/alternative, note that its top-level inline parts are also
counted via <literal>root</literal> <emphasis>disposition</emphasis>
(if <link linkend="count-alternatives">$count_alternatives</link> is
set).
</para>

<para>
Disposition is prefixed by either a <quote>+</quote> symbol or a
<quote>-</quote> symbol.  If it's a <quote>+</quote>, you're saying that
you want to allow this disposition and MIME type to qualify.  If it's a
<quote>-</quote>, you're saying that this disposition and MIME type is
an exception to previous <quote>+</quote> rules.  There are examples
below of how this is useful.
</para>

<para>
<emphasis>mime-type</emphasis> is the MIME type of the attachment you
want the command to affect.  A MIME type is always of the format
<literal>major/minor</literal>, where <literal>major</literal> describes
the broad category of document you're looking at, and
<literal>minor</literal> describes the specific type within that
category.  The major part of mime-type must be literal text (or the
special token <quote><literal>*</literal></quote>), but the minor part
may be a regular expression.  (Therefore,
<quote><literal>*/.*</literal></quote> matches any MIME type.)
</para>

<para>
The MIME types you give to the <command>attachments</command> directive
are a kind of pattern.  When you use the <command>attachments</command>
directive, the patterns you specify are added to a list.  When you use
<command>unattachments</command>, the pattern is removed from the list.
The patterns are not expanded and matched to specific MIME types at this
time &mdash; they're just text in a list.  They're only matched when
actually evaluating a message.
</para>

<para>
Some examples might help to illustrate.  The examples that are not
commented out define the default configuration of the lists.
</para>

<example id="ex-attach-count">
<title>Attachment counting</title>
<screen>
<emphasis role="comment">
# Removing a pattern from a list removes that pattern literally. It
# does not remove any type matching the pattern.
#
#  attachments   +A */.*
#  attachments   +A image/jpeg
#  unattachments +A */.*
#
# This leaves "attached" image/jpeg files on the allowed attachments
# list. It does not remove all items, as you might expect, because the
# second */.* is not a matching expression at this time.
#
# Remember: "unattachments" only undoes what "attachments" has done!
# It does not trigger any matching on actual messages.

# Qualify any MIME part with an "attachment" disposition, EXCEPT for
# text/x-vcard and application/pgp parts. (PGP parts are already known
# to mutt, and can be searched for with ~g, ~G, and ~k.)
#
# I've added x-pkcs7 to this, since it functions (for S/MIME)
# analogously to PGP signature attachments. S/MIME isn't supported
# in a stock mutt build, but we can still treat it specially here.
#
</emphasis>
attachments   +A */.*
attachments   -A text/x-vcard application/pgp.*
attachments   -A application/x-pkcs7-.*

<emphasis role="comment">
# Discount all MIME parts with an "inline" disposition, unless they're
# text/plain. (Why inline a text/plain part unless it's external to the
# message flow?)
</emphasis>
attachments   +I text/plain

<emphasis role="comment">
# These two lines make Mutt qualify MIME containers.  (So, for example,
# a message/rfc822 forward will count as an attachment.)  The first
# line is unnecessary if you already have "attach-allow */.*", of
# course.  These are off by default!  The MIME elements contained
# within a message/* or multipart/* are still examined, even if the
# containers themselves don't qualify.

#attachments  +A message/.* multipart/.*
#attachments  +I message/.* multipart/.*
</emphasis>

<emphasis role="comment">## You probably don't really care to know about deleted attachments.</emphasis>
attachments   -A message/external-body
attachments   -I message/external-body
</screen>
</example>

<para>
Entering the command <quote><command>attachments</command> ?</quote> as
a command will list your current settings in Muttrc format, so that it
can be pasted elsewhere.
</para>

<para>
Entering the command <quote><command>unattachments</command> *</quote> as
a command will Clear all attachment settings.
</para>
</sect1>

<sect1 id="mime-lookup">
<title>MIME Lookup</title>

<para>
Usage:
</para>

<cmdsynopsis>
<command>mime_lookup</command>
<arg choice="plain">
<replaceable>mimetype</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable>mimetype</replaceable>
</arg>

<command>unmime_lookup</command>
<group choice="req">
<arg choice="plain">
<replaceable>*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable>mimetype</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
Mutt's <command>mime_lookup</command> list specifies a list of MIME
types that should <emphasis>not</emphasis> be treated according to their
mailcap entry.  This option is designed to deal with binary types such
as <literal>application/octet-stream</literal>.  When an attachment's
MIME type is listed in <command>mime_lookup</command>, then the
extension of the filename will be compared to the list of extensions in
the <literal>mime.types</literal> file.  The MIME type associated with
this extension will then be used to process the attachment according to
the rules in the mailcap file and according to any other configuration
options (such as <command>auto_view</command>) specified.  Common usage
would be:
</para>

<screen>
mime_lookup application/octet-stream application/X-Lotus-Manuscript
</screen>

<para>
In addition, the <literal>unmime_lookup</literal> command may be used to
disable this feature for any particular MIME type if it had been set,
for example, in a global <literal>.muttrc</literal>.
</para>

</sect1>

</chapter>

<chapter id="optionalfeatures">
<title>Optional Features</title>

<sect1 id="optionalfeatures-notes">
<title>General Notes</title>

<sect2 id="compile-time-features">
<title>Enabling/Disabling Features</title>

<para>
Mutt supports several of optional features which can be enabled or
disabled at compile-time by giving the <emphasis>configure</emphasis>
script certain arguments. These are listed in the <quote>Optional
features</quote> section of the <emphasis>configure --help</emphasis>
output.
</para>

<para>
Which features are enabled or disabled can later be determined from the
output of <literal>mutt -v</literal>. If a compile option starts with
<quote>+</quote> it is enabled and disabled if prefixed with
<quote>-</quote>. For example, if Mutt was compiled using GnuTLS for
encrypted communication instead of OpenSSL, <literal>mutt -v</literal>
would contain:
</para>

<screen>
-USE_SSL_OPENSSL +USE_SSL_GNUTLS</screen>

</sect2>

<sect2 id="url-syntax">
<title>URL Syntax</title>

<para>
Mutt optionally supports the IMAP, POP3 and SMTP protocols which require
to access servers using URLs. The canonical syntax for specifying URLs
in Mutt is (an item enclosed in <literal>[]</literal> means it is
optional and may be omitted):
</para>

<screen>
proto[s]://[username[:password]@]server[:port][/path]
</screen>

<para>
<emphasis>proto</emphasis> is the communication protocol:
<literal>imap</literal> for IMAP, <literal>pop</literal> for POP3 and
<literal>smtp</literal> for SMTP. If <quote>s</quote> for <quote>secure
communication</quote> is appended, Mutt will attempt to establish an
encrypted communication using SSL or TLS.
</para>

<para>
Since all protocols supported by Mutt support/require authentication,
login credentials may be specified in the URL. This has the advantage
that multiple IMAP, POP3 or SMTP servers may be specified (which isn't
possible using, for example, <link
linkend="imap-user">$imap_user</link>). The username may contain the
<quote>@</quote> symbol being used by many mail systems as part of the
login name. The special characters <quote>/</quote>
(<literal>%2F</literal>), <quote>:</quote> (<literal>%3A</literal>) and
<quote>%</quote> (<literal>%25</literal>) have to be URL-encoded in
usernames using the <literal>%</literal>-notation.
</para>

<para>
A password can be given, too but is not recommended if the URL is
specified in a configuration file on disk.
</para>

<para>
If no port number is given, Mutt will use the system's default for the
given protocol (usually consulting <literal>/etc/services</literal>).
</para>

<para>
The optional path is only relevant for IMAP and ignored elsewhere.
</para>

<example id="ex-url">
<title>URLs</title>
<screen>
pops://host/
imaps://user@host/INBOX/Sent
smtp://user@host:587/
</screen>
</example>

</sect2>

</sect1>

<sect1 id="ssl">
<title>SSL/TLS Support</title>

<para>
If Mutt is compiled with IMAP, POP3 and/or SMTP support, it can also be
compiled with support for SSL or TLS using either OpenSSL or GnuTLS ( by
running the <emphasis>configure</emphasis> script with the
<emphasis>--enable-ssl=...</emphasis> option for OpenSSL or
<emphasis>--enable-gnutls=...</emphasis> for GnuTLS). Mutt can then
attempt to encrypt communication with remote servers if these protocols
are suffixed with <quote>s</quote> for <quote>secure
communication</quote>.
</para>

<sect2 id="starttls">
  <title>STARTTLS</title>
  <para>
    When non-secure URL protocols <literal>imap://</literal>,
    <literal>pop://</literal>, and <literal>smtp://</literal> are
    used, the initial connection to the server will be unencrypted.
    <literal>STARTTLS</literal> can be used to negotiate an encrypted
    connection after the initial unencrypted connection and exchange.
  </para>
  <para>
    Two configuration variables control Mutt's behavior with
    <literal>STARTTLS</literal>.  <link
    linkend="ssl-starttls">$ssl_starttls</link> will initiate
    <literal>STARTTLS</literal> if the server advertises support for
    it.  <link linkend="ssl-force-tls">$ssl_force_tls</link> will
    always try to initiate it, whether the server advertises support
    or not.
  </para>
  <para>
    Mutt <emphasis>highly recommends</emphasis> setting <link
    linkend="ssl-force-tls">$ssl_force_tls</link> unless you need to
    connect to an unencrypted server.  It's possible for an attacker
    to spoof interactions during the initial connection and hide
    support for <literal>STARTTLS</literal>.  The only way to prevent
    these attacks is by forcing <literal>STARTTLS</literal> with the
    <link linkend="ssl-force-tls">$ssl_force_tls</link> configuration
    variable.
  </para>
</sect2>

<sect2 id="secure-tunnel">
  <title>Tunnel</title>
  <para>
    When connecting through a <link linkend="tunnel">$tunnel</link>
    and <link linkend="tunnel-is-secure">$tunnel_is_secure</link> is
    set (Not the default!), Mutt will assume the connection to the server
    through the pipe is already secured.  Mutt will ignore <link
    linkend="ssl-starttls">$ssl_starttls</link> and <link
    linkend="ssl-force-tls">$ssl_force_tls</link>, behaving as if TLS
    has already been negotiated.
  </para>
  <para>
    When <link linkend="tunnel-is-secure">$tunnel_is_secure</link> is
    unset, Mutt will respect the values of <link
    linkend="ssl-starttls">$ssl_starttls</link> and <link
    linkend="ssl-force-tls">$ssl_force_tls</link>.  It is
    <emphasis>highly recommended</emphasis> to set <link
    linkend="ssl-force-tls">$ssl_force_tls</link> in this case, to
    force <literal>STARTTLS</literal> negotiation.  Note that doing so
    will prevent connection to an IMAP server configured for
    preauthentication (<literal>PREAUTH</literal>).  If you use this
    configuration, it is recommended to use a secure tunnel.
  </para>
</sect2>

</sect1>

<sect1 id="pop">
<title>POP3 Support</title>

<para>
If Mutt is compiled with POP3 support (by running the
<emphasis>configure</emphasis> script with the
<emphasis>--enable-pop</emphasis> flag), it has the ability to work with
mailboxes located on a remote POP3 server and fetch mail for local
browsing.
</para>

<para>
Remote POP3 servers can be accessed using URLs with the
<literal>pop</literal> protocol for unencrypted and
<literal>pops</literal> for encrypted communication, see <xref
linkend="url-syntax"/> for details.
</para>

<para>
Polling for new mail is more expensive over POP3 than locally. For this
reason the frequency at which Mutt will check for mail remotely can be
controlled by the <link
linkend="pop-checkinterval">$pop_checkinterval</link> variable, which
defaults to every 60 seconds.
</para>

<para>
POP is read-only which doesn't allow for some features like editing
messages or changing flags. However, using <xref
linkend="header-caching"/> and <xref linkend="body-caching"/> Mutt
simulates the new/old/read flags as well as flagged and replied.  Mutt
applies some logic on top of remote messages but cannot change them so
that modifications of flags are lost when messages are downloaded from
the POP server (either by Mutt or other tools).
</para>

<anchor id="fetch-mail"/>
<para>
Another way to access your POP3 mail is the
<literal>&lt;fetch-mail&gt;</literal> function (default: G).  It allows
to connect to <link linkend="pop-host">$pop_host</link>, fetch all your
new mail and place it in the local <link
linkend="spoolfile">$spoolfile</link>.  After this point, Mutt runs
exactly as if the mail had always been local.
</para>

<note>
<para>
If you only need to fetch all messages to a local mailbox you should
consider using a specialized program, such as
<literal>fetchmail(1)</literal>, <literal>getmail(1)</literal> or
similar.
</para>
</note>

</sect1>

<sect1 id="imap">
<title>IMAP Support</title>

<para>
If Mutt was compiled with IMAP support (by running the
<emphasis>configure</emphasis> script with the
<emphasis>--enable-imap</emphasis> flag), it has the ability to work
with folders located on a remote IMAP server.
</para>

<para>
You can access the remote inbox by selecting the folder by its URL (see
<xref linkend="url-syntax"/> for details) using the
<literal>imap</literal> or <literal>imaps</literal> protocol.
Alternatively, a pine-compatible notation is also supported, i.e.
<literal>{[username@]imapserver[:port][/ssl]}path/to/folder</literal>
</para>

<para>
Note that not all servers use <quote>/</quote> as the hierarchy
separator.  Mutt should correctly notice which separator is being used
by the server and convert paths accordingly.
</para>

<para>
When browsing folders on an IMAP server, you can toggle whether to look
at only the folders you are subscribed to, or all folders with the
<emphasis>toggle-subscribed</emphasis> command.  See also the <link
linkend="imap-list-subscribed">$imap_list_subscribed</link> variable.
</para>

<para>
Polling for new mail on an IMAP server can cause noticeable delays. So,
you'll want to carefully tune the <link
linkend="mail-check">$mail_check</link> and <link
linkend="timeout">$timeout</link> variables. Reasonable values are:
</para>

<screen>
set mail_check=90
set timeout=15
</screen>

<para>
with relatively good results even over slow modem lines.
</para>

<note>
<para>
Note that if you are using mbox as the mail store on UW servers prior to
v12.250, the server has been reported to disconnect a client if another
client selects the same folder.
</para>
</note>

<sect2 id="imap-browser">
<title>The IMAP Folder Browser</title>

<para>
As of version 1.2, Mutt supports browsing mailboxes on an IMAP
server. This is mostly the same as the local file browser, with the
following differences:
</para>

<itemizedlist>
<listitem>

<para>
In lieu of file permissions, Mutt displays the string
<quote>IMAP</quote>, possibly followed by the symbol <quote>+</quote>,
indicating that the entry contains both messages and subfolders. On
Cyrus-like servers folders will often contain both messages and
subfolders.  A mailbox name with a trailing delimiter (usually
<quote>/</quote> or <quote>.</quote>) indicates subfolders.
</para>
</listitem>
<listitem>

<para>
For the case where an entry can contain both messages and subfolders,
the selection key (bound to <literal>enter</literal> by default) will
choose to descend into the subfolder view. If you wish to view the
messages in that folder, you must use <literal>view-file</literal>
instead (bound to <literal>space</literal> by default).
</para>
</listitem>
<listitem>

<para>
You can create, delete and rename mailboxes with the
<literal>&lt;create-mailbox&gt;</literal>,
<literal>&lt;delete-mailbox&gt;</literal>, and
<literal>&lt;rename-mailbox&gt;</literal> commands (default bindings:
<literal>C</literal>, <literal>d</literal> and <literal>r</literal>,
respectively). You may also <literal>&lt;subscribe&gt;</literal> and
<literal>&lt;unsubscribe&gt;</literal> to mailboxes (normally these are
bound to <literal>s</literal> and <literal>u</literal>, respectively).
</para>
</listitem>

</itemizedlist>

</sect2>

<sect2 id="imap-authentication">
<title>Authentication</title>

<para>
Mutt supports four authentication methods with IMAP servers: SASL,
GSSAPI, CRAM-MD5, and LOGIN (there is a patch by Grant Edwards to add
NTLM authentication for you poor exchange users out there, but it has
yet to be integrated into the main tree). There is also support for the
pseudo-protocol ANONYMOUS, which allows you to log in to a public IMAP
server without having an account. To use ANONYMOUS, simply make your
username blank or <quote>anonymous</quote>.
</para>

<para>
SASL is a special super-authenticator, which selects among several
protocols (including GSSAPI, CRAM-MD5, ANONYMOUS, and DIGEST-MD5) the
most secure method available on your host and the server. Using some of
these methods (including DIGEST-MD5 and possibly GSSAPI), your entire
session will be encrypted and invisible to those teeming network
snoops. It is the best option if you have it. To use it, you must have
the Cyrus SASL library installed on your system and compile Mutt with
the <emphasis>--with-sasl</emphasis> flag.
</para>

<para>
Mutt will try whichever methods are compiled in and available on the
server, in the following order: SASL, ANONYMOUS, GSSAPI, CRAM-MD5,
LOGIN.
</para>

<para>
There are a few variables which control authentication:
</para>

<itemizedlist>
<listitem>

<para>
<link linkend="imap-user">$imap_user</link> - controls the username
under which you request authentication on the IMAP server, for all
authenticators. This is overridden by an explicit username in the
mailbox path (i.e. by using a mailbox name of the form
<literal>{user@host}</literal>).
</para>
</listitem>
<listitem>

<para>
<link linkend="imap-pass">$imap_pass</link> - a password which you may
preset, used by all authentication methods where a password is needed.
</para>
</listitem>
<listitem>

<para>
<link linkend="imap-authenticators">$imap_authenticators</link> - a
colon-delimited list of IMAP authentication methods to try, in the order
you wish to try them. If specified, this overrides Mutt's default
(attempt everything, in the order listed above).
</para>
</listitem>

</itemizedlist>

</sect2>

</sect1>

<sect1 id="smtp">
<title>SMTP Support</title>

<para>
Besides supporting traditional mail delivery through a
sendmail-compatible program, Mutt supports delivery through SMTP if it
was configured and built with <literal>--enable-smtp</literal>.
</para>

<para>
If the configuration variable <link linkend="smtp-url">$smtp_url</link>
is set, Mutt will contact the given SMTP server to deliver messages; if
it is unset, Mutt will use the program specified by <link
linkend="sendmail">$sendmail</link>.
</para>

<para>
For details on the URL syntax, please see <xref linkend="url-syntax"/>.
</para>

<para>
The built-in SMTP support supports encryption (the
<literal>smtps</literal> protocol using SSL or TLS) as well as SMTP
authentication using SASL. The authentication mechanisms for SASL are
specified in <link
linkend="smtp-authenticators">$smtp_authenticators</link> defaulting to
an empty list which makes Mutt try all available methods from
most-secure to least-secure.
</para>

</sect1>

<sect1 id="oauth">
<title>OAUTHBEARER Support</title>

<para>
Preliminary OAUTH support for IMAP, POP, and SMTP is provided via
external scripts.
</para>

<para>
At least for Gmail, you can use the <literal>oauth2.py</literal>
script from Google's gmail-oauth2-tools: <ulink
url="https://github.com/google/gmail-oauth2-tools/blob/master/python/oauth2.py"
>https://github.com/google/gmail-oauth2-tools/blob/master/python/oauth2.py</ulink>
</para>

<para>
You'll need to get your own oauth client credentials for Gmail here:
<ulink url="https://console.developers.google.com/apis/credentials"
>https://console.developers.google.com/apis/credentials</ulink>
</para>

<para>
Then, you'd use <literal>oauth2.py</literal> with
<literal>--generate_oauth2_token</literal> to get a refresh token, and
configure mutt with:
</para>

<screen>
set imap_authenticators="oauthbearer"
set imap_oauth_refresh_command="/path/to/oauth2.py --quiet --user=[email_address]\
    --client_id=[client_id] --client_secret=[client_secret]\
    --refresh_token=[refresh_token]"
</screen>

<para>
Substitute pop or smtp for imap in the above example to configure for those.
</para>

<para>
An alternative script is <ulink
url="https://gitlab.com/muttmua/mutt/tree/master/contrib/mutt_oauth2.py"
>contrib/mutt_oauth2.py</ulink> script.  For more details see <ulink
url="https://gitlab.com/muttmua/mutt/tree/master/contrib/mutt_oauth2.py.README"
>contrib/mutt_oauth2.py.README</ulink>.
</para>

<sect2 id="xoauth2">
  <title>XOAUTH2 Support</title>

  <para>
    Support for the deprecated XOAUTH2 protocol is also available.  To
    enable this, add <quote>xoauth2</quote> to the
    <link linkend="imap-authenticators">$imap_authenticators</link>,
    <link linkend="pop-authenticators">$pop_authenticators</link>, or
    <link linkend="smtp-authenticators">$smtp_authenticators</link> config
    variables.  XOAUTH2 uses the same refresh command configuration variables
    as OAUTHBEARER:
    <link linkend="imap-oauth-refresh-command">$imap_oauth_refresh_command</link>,
    <link linkend="pop-oauth-refresh-command">$pop_oauth_refresh_command</link>, and
    <link linkend="smtp-oauth-refresh-command">$smtp_oauth_refresh_command</link>.
    Those will need to be set to a script to generate the appropriate XOAUTH2
    token.
  </para>
</sect2>

</sect1>

<sect1 id="account-hook">
<title>Managing Multiple Accounts</title>

<para>
Usage:
</para>

<cmdsynopsis>
<command>account-hook</command>
<arg choice="plain">
<replaceable class="parameter">regexp</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">command</replaceable>
</arg>
</cmdsynopsis>

<para>
If you happen to have accounts on multiple IMAP, POP and/or SMTP
servers, you may find managing all the authentication settings
inconvenient and error-prone. The <link
linkend="account-hook"><command>account-hook</command></link> command
may help. This hook works like <link
linkend="folder-hook"><command>folder-hook</command></link> but is
invoked whenever Mutt needs to access a remote mailbox (including inside
the folder browser), not just when you open the mailbox. This includes
(for example) polling for new mail, storing Fcc messages and saving
messages to a folder. As a consequence, <link
linkend="account-hook"><command>account-hook</command></link> should
only be used to set connection-related settings such as passwords or
tunnel commands but not settings such as sender address or name (because
in general it should be considered unpredictable which <link
linkend="account-hook"><command>account-hook</command></link> was last
used).
</para>

<para>
Some examples:
</para>

<screen>
account-hook . 'unset imap_user; unset imap_pass; unset tunnel'
account-hook imap://host1/ 'set imap_user=me1 imap_pass=foo'
account-hook imap://host2/ 'set tunnel="ssh host2 /usr/libexec/imapd"'
account-hook smtp://user@host3/ 'set tunnel="ssh host3 /usr/libexec/smtpd"'
</screen>

<para>
To manage multiple accounts with, for example, different values of <link
linkend="record">$record</link> or sender addresses, <link
linkend="folder-hook"><command>folder-hook</command></link> has to be
used together with the <link
linkend="mailboxes"><command>mailboxes</command></link> command.
</para>

<example id="ex-multiaccount">
<title>Managing multiple accounts</title>
<screen>
mailboxes imap://user@host1/INBOX
folder-hook imap://user@host1/ 'set folder=imap://host1/ ; set record=+INBOX/Sent'

mailboxes imap://user@host2/INBOX
folder-hook imap://user@host2/ 'set folder=imap://host2/ ; set record=+INBOX/Sent'
</screen>
</example>

<para>
In example <xref linkend="ex-multiaccount"/> the folders are defined
using <link linkend="mailboxes"><command>mailboxes</command></link> so
Mutt polls them for new mail. Each <link
linkend="folder-hook"><command>folder-hook</command></link> triggers
when one mailbox below each IMAP account is opened and sets <link
linkend="folder">$folder</link> to the account's root folder. Next, it
sets <link linkend="record">$record</link> to the
<emphasis>INBOX/Sent</emphasis> folder below the newly set <link
linkend="folder">$folder</link>. Please notice that the value the
<quote>+</quote> <link linkend="shortcuts">mailbox shortcut</link>
refers to depends on the <emphasis>current</emphasis> value of <link
linkend="folder">$folder</link> and therefore has to be set separately
per account. Setting other values like <link linkend="from">$from</link>
or <link linkend="signature">$signature</link> is analogous to setting
<link linkend="record">$record</link>.
</para>

</sect1>

<sect1 id="caching">
<title>Local Caching</title>

<para>
Mutt contains two types of local caching: <emphasis>(1)</emphasis> the
so-called <quote>header caching</quote> and <emphasis>(2)</emphasis> the
so-called <quote>body caching</quote> which are both described in this
section.
</para>

<para>
Header caching is optional as it depends on external libraries, body
caching is always enabled if Mutt is compiled with POP and/or IMAP
support as these use it (body caching requires no external library).
</para>

<sect2 id="header-caching">
<title>Header Caching</title>

<para>
Mutt provides optional support for caching message headers for the
following types of folders: IMAP, POP, Maildir and MH. Header caching
greatly speeds up opening large folders because for remote folders,
headers usually only need to be downloaded once. For Maildir and MH,
reading the headers from a single file is much faster than looking at
possibly thousands of single files (since Maildir and MH use one file
per message.)
</para>

<para>
Header caching can be enabled via the configure script and the
<emphasis>--enable-hcache</emphasis> option. It's not turned on by
default because external database libraries are required: one of
tokyocabinet, kyotocabinet, lmdb, qdbm, gdbm or bdb must be present.
</para>

<para>
If enabled, <link linkend="header-cache">$header_cache</link> can be
used to either point to a file or a directory. If set to point to a
file, one database file for all folders will be used (which may result
in lower performance), but one file per folder if it points to a
directory.
</para>

</sect2>

<sect2 id="body-caching">
<title>Body Caching</title>

<para>
Both cache methods can be combined using the same directory for storage
(and for IMAP/POP even provide meaningful file names) which simplifies
manual maintenance tasks.
</para>

<para>
In addition to caching message headers only, Mutt can also cache whole
message bodies. This results in faster display of messages for POP and
IMAP folders because messages usually have to be downloaded only once.
</para>

<para>
For configuration, the variable <link linkend="message-cachedir"
>$message_cachedir</link> must point to a directory. There, Mutt will
create a hierarchy of subdirectories named like the account and mailbox
path the cache is for.
</para>

</sect2>

<sect2 id="cache-dirs">
<title>Cache Directories</title>

<para>
For using both, header and body caching, <link
linkend="header-cache">$header_cache</link> and <link
linkend="message-cachedir" >$message_cachedir</link> can be safely set
to the same value.
</para>

<para>
In a header or body cache directory, Mutt creates a directory hierarchy
named like: <literal>proto:user@hostname</literal> where
<literal>proto</literal> is either <quote>pop</quote> or
<quote>imap.</quote> Within there, for each folder, Mutt stores messages
in single files and header caches in files with the
<quote>.hcache</quote> extension.  All files can be removed as needed if
the consumed disk space becomes an issue as Mutt will silently fetch
missing items again. Pathnames are always stored in UTF-8 encoding.
</para>

<para>
For Maildir and MH, the header cache files are named after the MD5
checksum of the path.
</para>

</sect2>

<sect2 id="maint-cache">
<title>Maintenance</title>

<para>
Mutt does not (yet) support maintenance features for header cache
database files so that files have to be removed in case they grow too
big. It depends on the database library used for header caching whether
disk space freed by removing messages is re-used.
</para>

<para>
For body caches, Mutt can keep the local cache in sync with the remote
mailbox if the <link
linkend="message-cache-clean">$message_cache_clean</link> variable is
set. Cleaning means to remove messages from the cache which are no
longer present in the mailbox which only happens when other mail clients
or instances of Mutt using a different body cache location delete
messages (Mutt itself removes deleted messages from the cache when
syncing a mailbox). As cleaning can take a noticeable amount of time, it
should not be set in general but only occasionally.
</para>

</sect2>

</sect1>

<sect1 id="exact-address">
<title>Exact Address Generation</title>

<para>
Mutt supports the <quote>Name &lt;user@host&gt;</quote> address syntax
for reading and writing messages, the older <quote>user@host
(Name)</quote> syntax is only supported when reading messages. The
<emphasis>--enable-exact-address</emphasis> switch can be given to
configure to build it with write-support for the latter
syntax. <literal>EXACT_ADDRESS</literal> in the output of <literal>mutt
-v</literal> indicates whether it's supported.
</para>
<para>
Note: If the full address contains non-ascii characters, or sequences
that require RFC 2047 encoding, Mutt reverts to writing out the
normalized <quote>Name &lt;user@host&gt;</quote> form, in order to
generate legal output.
</para>

</sect1>

<sect1 id="sending-mixmaster">
<title>Sending Anonymous Messages via Mixmaster</title>

<para>
You may also have compiled Mutt to co-operate with Mixmaster, an
anonymous remailer.  Mixmaster permits you to send your messages
anonymously using a chain of remailers. Mixmaster support in Mutt is for
mixmaster version 2.04 or later.
</para>

<para>
To use it, you'll have to obey certain restrictions.  Most important,
you cannot use the <literal>Cc</literal> and <literal>Bcc</literal>
headers.  To tell Mutt to use mixmaster, you have to select a remailer
chain, using the mix function on the compose menu.
</para>

<para>
The chain selection screen is divided into two parts.  In the (larger)
upper part, you get a list of remailers you may use.  In the lower part,
you see the currently selected chain of remailers.
</para>

<para>
You can navigate in the chain using the
<literal>&lt;chain-prev&gt;</literal> and
<literal>&lt;chain-next&gt;</literal> functions, which are by default
bound to the left and right arrows and to the <literal>h</literal> and
<literal>l</literal> keys (think vi keyboard bindings).  To insert a
remailer at the current chain position, use the
<literal>&lt;insert&gt;</literal> function.  To append a remailer behind
the current chain position, use <literal>&lt;select-entry&gt;</literal>
or <literal>&lt;append&gt;</literal>.  You can also delete entries from
the chain, using the corresponding function.  Finally, to abandon your
changes, leave the menu, or <literal>&lt;accept&gt;</literal> them
pressing (by default) the <literal>Return</literal> key.
</para>

<para>
Note that different remailers do have different capabilities, indicated
in the %c entry of the remailer menu lines (see <link
linkend="mix-entry-format">$mix_entry_format</link>).  Most important is
the <quote>middleman</quote> capability, indicated by a capital
<quote>M</quote>: This means that the remailer in question cannot be
used as the final element of a chain, but will only forward messages to
other mixmaster remailers.  For details on the other capabilities,
please have a look at the mixmaster documentation.
</para>

</sect1>

<sect1 id="sidebar">
  <title>Sidebar</title>
  <subtitle>Overview of mailboxes</subtitle>

  <sect2 id="sidebar-intro">
    <title>Introduction</title>

    <para>
      The Sidebar shows a list of all your mailboxes.  The list can be
      turned on and off, it can be themed and the list style can be
      configured.
    </para>
  </sect2>

  <sect2 id="sidebar-variables">
    <title>Variables</title>

    <table id="table-sidebar-variables">
      <title>Sidebar Variables</title>
      <tgroup cols="3">
	<thead>
	  <row>
	    <entry>Name</entry>
	    <entry>Type</entry>
	    <entry>Default</entry>
	  </row>
	</thead>
	<tbody>
	  <row>
	    <entry><literal>sidebar_delim_chars</literal></entry>
	    <entry>string</entry>
	    <entry><literal>/.</literal></entry>
	  </row>
	  <row>
	    <entry><literal>sidebar_divider_char</literal></entry>
	    <entry>string</entry>
	    <entry><literal>|</literal></entry>
	  </row>
	  <row>
	    <entry><literal>sidebar_folder_indent</literal></entry>
	    <entry>boolean</entry>
	    <entry><literal>no</literal></entry>
	  </row>
	  <row>
	    <entry><literal>sidebar_format</literal></entry>
	    <entry>string</entry>
	    <entry><literal>%B%*  %n</literal></entry>
	  </row>
	  <row>
	    <entry><literal>sidebar_indent_string</literal></entry>
	    <entry>string</entry>
	    <entry><literal>&nbsp;&nbsp;</literal> (two spaces)</entry>
	  </row>
	  <row>
	    <entry><literal>sidebar_new_mail_only</literal></entry>
	    <entry>boolean</entry>
	    <entry><literal>no</literal></entry>
	  </row>
	  <row>
	    <entry><literal>sidebar_next_new_wrap</literal></entry>
	    <entry>boolean</entry>
	    <entry><literal>no</literal></entry>
	  </row>
	  <row>
	    <entry><literal>sidebar_short_path</literal></entry>
	    <entry>boolean</entry>
	    <entry><literal>no</literal></entry>
	  </row>
	  <row>
	    <entry><literal>sidebar_sort_method</literal></entry>
	    <entry>enum</entry>
	    <entry><literal>unsorted</literal></entry>
	  </row>
	  <row>
	    <entry><literal>sidebar_visible</literal></entry>
	    <entry>boolean</entry>
	    <entry><literal>no</literal></entry>
	  </row>
	  <row>
	    <entry><literal>sidebar_width</literal></entry>
	    <entry>number</entry>
	    <entry><literal>20</literal></entry>
	  </row>
	</tbody>
      </tgroup>
    </table>
  </sect2>

  <sect2 id="sidebar-functions">
    <title>Functions</title>

    <para>
      Sidebar adds the following functions to Mutt.
      By default, none of them are bound to keys.
    </para>

    <table id="table-sidebar-functions">
      <title>Sidebar Functions</title>
      <tgroup cols="3">
	<thead>
	  <row>
	    <entry>Menus</entry>
	    <entry>Function</entry>
	    <entry>Description</entry>
	  </row>
	</thead>
	<tbody>
	  <row>
	    <entry>index,pager</entry>
	    <entry><literal>&lt;sidebar-next&gt;</literal></entry>
	    <entry>Move the highlight to next mailbox</entry>
	  </row>
	  <row>
	    <entry>index,pager</entry>
	    <entry><literal>&lt;sidebar-next-new&gt;</literal></entry>
	    <entry>Move the highlight to next mailbox with new mail</entry>
	  </row>
	  <row>
	    <entry>index,pager</entry>
	    <entry><literal>&lt;sidebar-open&gt;</literal></entry>
	    <entry>Open highlighted mailbox</entry>
	  </row>
	  <row>
	    <entry>index,pager</entry>
	    <entry><literal>&lt;sidebar-page-down&gt;</literal></entry>
	    <entry>Scroll the Sidebar down 1 page</entry>
	  </row>
	  <row>
	    <entry>index,pager</entry>
	    <entry><literal>&lt;sidebar-page-up&gt;</literal></entry>
	    <entry>Scroll the Sidebar up 1 page</entry>
	  </row>
	  <row>
	    <entry>index,pager</entry>
	    <entry><literal>&lt;sidebar-prev&gt;</literal></entry>
	    <entry>Move the highlight to previous mailbox</entry>
	  </row>
	  <row>
	    <entry>index,pager</entry>
	    <entry><literal>&lt;sidebar-prev-new&gt;</literal></entry>
	    <entry>Move the highlight to previous mailbox with new mail</entry>
	  </row>
	  <row>
	    <entry>index,pager</entry>
	    <entry><literal>&lt;sidebar-toggle-visible&gt;</literal></entry>
	    <entry>Make the Sidebar (in)visible</entry>
	  </row>
	</tbody>
      </tgroup>
    </table>
  </sect2>

  <sect2 id="sidebar-whitelist">
    <title>Commands</title>
    <cmdsynopsis>
      <command>sidebar_whitelist</command>
      <arg choice="plain">
	<replaceable class="parameter">mailbox</replaceable>
      </arg>
      <arg choice="opt" rep="repeat">
	<replaceable class="parameter">mailbox</replaceable>
      </arg>

      <command>unsidebar_whitelist</command>
      <group choice="req">
      <arg choice="plain">
	<replaceable class="parameter">*</replaceable>
      </arg>
      <arg choice="plain" rep="repeat">
	<replaceable class="parameter">mailbox</replaceable>
      </arg>
      </group>
    </cmdsynopsis>

    <para>
      This command specifies mailboxes that will always be displayed
      in the sidebar, even if <link
      linkend="sidebar-new-mail-only">$sidebar_new_mail_only</link>
      is set and the mailbox does not contain new mail.
    </para>

    <para>
      The <quote>unsidebar_whitelist</quote> command is used to remove a mailbox from
      the list of whitelisted mailboxes. Use <quote>unsidebar_whitelist *</quote>
      to remove all mailboxes.
    </para>
  </sect2>

  <sect2 id="sidebar-colors">
    <title>Colors</title>

    <table id="table-sidebar-colors">
      <title>Sidebar Colors</title>
      <tgroup cols="3">
	<thead>
	  <row>
	    <entry>Name</entry>
	    <entry>Default Color</entry>
	    <entry>Description</entry>
	  </row>
	</thead>
	<tbody>
	  <row>
	    <entry><literal>sidebar_divider</literal></entry>
	    <entry>default</entry>
	    <entry>The dividing line between the Sidebar and the Index/Pager panels</entry>
	  </row>
	  <row>
	    <entry><literal>sidebar_flagged</literal></entry>
	    <entry>default</entry>
	    <entry>Mailboxes containing flagged mail</entry>
	  </row>
	  <row>
	    <entry><literal>sidebar_highlight</literal></entry>
	    <entry>underline</entry>
	    <entry>Cursor to select a mailbox</entry>
	  </row>
	  <row>
	    <entry><literal>sidebar_indicator</literal></entry>
	    <entry>mutt <literal>indicator</literal></entry>
	    <entry>The mailbox open in the Index panel</entry>
	  </row>
	  <row>
	    <entry><literal>sidebar_new</literal></entry>
	    <entry>default</entry>
	    <entry>Mailboxes containing new mail</entry>
	  </row>
	  <row>
	    <entry><literal>sidebar_spoolfile</literal></entry>
	    <entry>default</entry>
	    <entry>Mailbox that receives incoming mail</entry>
	  </row>
	</tbody>
      </tgroup>
    </table>

    <para>
    If the <literal>sidebar_indicator</literal> color isn't set, then the default Mutt
    indicator color will be used (the color used in the index panel).
    </para>
  </sect2>

  <sect2 id="sidebar-sort">
    <title>Sort</title>

    <table id="table-sidebar-sort">
      <title>Sidebar Sort</title>
      <tgroup cols="2">
	<thead>
	  <row>
	    <entry>Sort</entry>
	    <entry>Description</entry>
	  </row>
	</thead>
	<tbody>
	  <row>
	    <entry><literal>alpha</literal></entry>
	    <entry>Alphabetically by path or label</entry>
	  </row>
	  <row>
	    <entry><literal>count</literal></entry>
	    <entry>Total number of messages</entry>
	  </row>
	  <row>
	    <entry><literal>flagged</literal></entry>
	    <entry>Number of flagged messages</entry>
	  </row>
	  <row>
	    <entry><literal>name</literal></entry>
	    <entry>Alphabetically by path or label</entry>
	  </row>
	  <row>
	    <entry><literal>new</literal></entry>
	    <entry>Number of unread messages</entry>
	  </row>
	  <row>
	    <entry><literal>path</literal></entry>
	    <entry>Alphabetically by path (ignores label)</entry>
	  </row>
	  <row>
	    <entry><literal>unread</literal></entry>
	    <entry>Number of unread messages</entry>
	  </row>
	  <row>
	    <entry><literal>unsorted</literal></entry>
	    <entry>Do not resort the paths</entry>
	  </row>
	</tbody>
      </tgroup>
    </table>
  </sect2>


  <sect2 id="sidebar-see-also">
    <title>See Also</title>

    <itemizedlist>
      <listitem><para><link linkend="regexp">Regular Expressions</link></para></listitem>
      <listitem><para><link linkend="patterns">Patterns</link></para></listitem>
      <listitem><para><link linkend="color">Color command</link></para></listitem>
    </itemizedlist>
  </sect2>
</sect1>

<sect1 id="compress">
  <title>Compressed Folders Feature</title>
  <subtitle>Read from/write to compressed mailboxes</subtitle>

  <sect2 id="compress-intro">
    <title>Introduction</title>

    <para>
      The Compressed Folder patch allows Mutt to read mailbox files that are
      compressed.  But it isn't limited to compressed files.  It works well
      with encrypted files, too.  In fact, if you can create a program/script
      to convert to and from your format, then Mutt can read it.
    </para>

    <para>
      The patch adds three hooks to Mutt: <literal>open-hook</literal>,
      <literal>close-hook</literal> and <literal>append-hook</literal>.  They
      define commands to: uncompress a file; compress a file; append
      messages to an already compressed file.
    </para>

    <para>
      There are some examples of both compressed and encrypted files,
      later.  For now, the documentation will just concentrate on
      compressed files.
    </para>

  </sect2>

  <sect2 id="compress-commands">
    <title>Commands</title>
    <cmdsynopsis>
      <command>open-hook</command>
      <arg choice="plain">
        <replaceable class="parameter">pattern</replaceable>
      </arg>
      <arg choice="plain">
        <replaceable class="parameter">shell-command</replaceable>
      </arg>
      <command>close-hook</command>
      <arg choice="plain">
        <replaceable class="parameter">pattern</replaceable>
      </arg>
      <arg choice="plain">
        <replaceable class="parameter">shell-command</replaceable>
      </arg>
      <command>append-hook</command>
      <arg choice="plain">
        <replaceable class="parameter">pattern</replaceable>
      </arg>
      <arg choice="plain">
        <replaceable class="parameter">shell-command</replaceable>
      </arg>
    </cmdsynopsis>

    <para>
      The shell-command must contain two placeholders for filenames:
      <literal>%f</literal> and <literal>%t</literal>.  These represent
      <quote>from</quote> and <quote>to</quote> filenames.  These placeholders
      should be placed inside single-quotes to prevent unintended shell
      expansions.
    </para>

    <para>
      If you need the exact string <quote>%f</quote> or <quote>%t</quote> in your
      command, simply double up the <quote>%</quote> character, e.g.
      <quote>%%f</quote> or <quote>%%t</quote>.
    </para>

    <table id="table-compress-optional">
      <title>Not all Hooks are Required</title>
      <tgroup cols="5">
        <thead>
          <row>
            <entry>Open</entry>
            <entry>Close</entry>
            <entry>Append</entry>
            <entry>Effect</entry>
            <entry>Useful if</entry>
          </row>
        </thead>
        <tbody>
          <row>
            <entry>Open</entry>
            <entry>-</entry>
            <entry>-</entry>
            <entry>Folder is readonly</entry>
            <entry>The folder is just a backup</entry>
          </row>
          <row>
            <entry>Open</entry>
            <entry>Close</entry>
            <entry>-</entry>
            <entry>Folder is read/write, but the entire folder must be
              written if anything is changed</entry>
            <entry>Your compression format doesn't support appending</entry>
          </row>
          <row>
            <entry>Open</entry>
            <entry>Close</entry>
            <entry>Append</entry>
            <entry>Folder is read/write and emails can be efficiently added
              to the end</entry>
            <entry>Your compression format supports appending</entry>
          </row>
          <row>
            <entry>Open</entry>
            <entry>-</entry>
            <entry>Append</entry>
            <entry>Folder is readonly, but can be appended to</entry>
            <entry>You want to store emails, but never change them</entry>
          </row>
        </tbody>
      </tgroup>
    </table>

    <note>
      <para>The command:</para>
      <itemizedlist>
        <listitem><para>should return a non-zero exit status on failure</para></listitem>
        <listitem><para>should not delete any files</para></listitem>
      </itemizedlist>
    </note>

    <sect3 id="open-hook">
      <title>Read from compressed mailbox</title>

      <screen>open-hook regexp shell-command</screen>

      <para>
        If Mutt is unable to open a file, it then looks for
        <literal>open-hook</literal> that matches the filename.
      </para>

      <para>
        If your compression program doesn't have a well-defined extension,
        then you can use <literal>.</literal> as the regexp.
      </para>

      <example id="compress-open-hook-example">
        <title>Example of open-hook</title>

        <screen>open-hook '\.gz$' &quot;gzip -cd '%f' &gt; '%t'&quot;</screen>

        <itemizedlist>
          <listitem><para>Mutt finds a file, <quote>example.gz</quote>,
              that it can't read</para></listitem>
          <listitem><para>Mutt has an <literal>open-hook</literal>
              whose regexp matches the filename:
              <literal>\.gz$</literal></para></listitem>
          <listitem><para>Mutt uses the command <literal>gzip -cd</literal>
              to create a temporary file that it <emphasis>can</emphasis>
              read</para></listitem>
        </itemizedlist>
      </example>
    </sect3>

    <sect3 id="close-hook">
      <title>Write to a compressed mailbox</title>

      <screen>close-hook regexp shell-command</screen>

      <para>
        When Mutt has finished with a compressed mail folder, it will look
        for a matching <literal>close-hook</literal> to recompress the file.
        This hook is <link linkend="table-compress-optional">optional</link>.
      </para>

      <note>
        <para>
          If the folder has not been modified, the
          <literal>close-hook</literal> will not be called.
        </para>
      </note>

      <example id="compress-close-hook-example">
        <title>Example of close-hook</title>

        <screen>close-hook '\.gz$' &quot;gzip -c '%t' &gt; '%f'&quot;</screen>

        <itemizedlist>
          <listitem><para>Mutt has finished with a folder, <quote>example.gz</quote>,
              that it opened with <literal>open-hook</literal></para></listitem>
          <listitem><para>The folder has been modified</para></listitem>
          <listitem><para>Mutt has a <literal>close-hook</literal> whose regexp
              matches the filename: <literal>\.gz$</literal></para></listitem>
          <listitem><para>Mutt uses the command <literal>gzip -c</literal>
              to create a new compressed file</para></listitem>
        </itemizedlist>
      </example>
    </sect3>

    <sect3 id="append-hook">
      <title>Append to a compressed mailbox</title>

      <screen>append-hook regexp shell-command</screen>

      <para>
        When Mutt wants to append an email to a compressed mail folder, it
        will look for a matching <literal>append-hook</literal>.
        This hook is <link linkend="table-compress-optional">optional</link>.
      </para>

      <para>
        Using the <literal>append-hook</literal> will save time, but
        Mutt won't be able to determine the type of the mail folder
        inside the compressed file.
      </para>

      <para>
        Mutt will <emphasis>assume</emphasis> the type to be that of
        the <literal>$mbox_type</literal> variable.  Mutt also uses
        this type for temporary files.
      </para>

      <para>
        Mutt will only use the <literal>append-hook</literal> for existing files.
        The <literal>close-hook</literal> will be used for empty, or missing files.
      </para>

      <note>
        <para>
          If your command writes to stdout, it is vital that you use
          <literal>&gt;&gt;</literal> in the <quote>append-hook</quote>.
          If not, data will be lost.
        </para>
      </note>

      <example id="compress-append-hook-example">
        <title>Example of append-hook</title>

        <screen>append-hook '\.gz$' &quot;gzip -c '%t' &gt;&gt; '%f'&quot;</screen>

        <itemizedlist>
          <listitem><para>Mutt wants to append an email to a folder, <quote>example.gz</quote>,
              that it opened with <literal>open-hook</literal></para></listitem>
          <listitem><para>Mutt has an <literal>append-hook</literal> whose regexp matches
              the filename: <literal>\.gz$</literal></para></listitem>
          <listitem><para>Mutt knows the mailbox type from the <literal>$mbox</literal>
              variable</para></listitem>
          <listitem><para>Mutt uses the command <literal>gzip -c</literal>
              to append to an existing compressed file</para></listitem>
        </itemizedlist>
      </example>

    </sect3>

    <sect3 id="compress-empty">
      <title>Empty Files</title>

      <para>
        Mutt assumes that an empty file is not compressed.  In this
        situation, unset <link linkend="save-empty">$save_empty</link>, so
        that the compressed file will be removed if you delete all of the
        messages.
      </para>
    </sect3>

    <sect3 id="compress-security">
      <title>Security</title>

      <para>
        Encrypted files are decrypted into temporary files which are
        stored in the <link linkend="tmpdir">$tmpdir</link> directory.
        This could be a security risk.
      </para>
    </sect3>
  </sect2>
</sect1>

<sect1 id="autocryptdoc">
  <title>Autocrypt</title>

  <para>
    Mutt can be compiled with Autocrypt support by running
    <literal>configure</literal> with the
    <literal>--enable-autocrypt</literal> flag.  Autocrypt provides
    easy to use, passive protection against data collection.  Keys are
    distributed via an <literal>Autocrypt:</literal> header added to
    emails.  It does <emphasis>not</emphasis> protect against active
    adversaries, and so should not be considered a substitute for
    normal encryption via your keyring, using key signing and the web
    of trust to verify identities.  With an understanding of these
    limitations, Autocrypt still provides an easy way to minimize
    cleartext emails sent between common correspondents, without
    having to explicitly exchange keys.  More information can be found
    at <ulink
    url="https://autocrypt.org/">https://autocrypt.org/</ulink>.
  </para>

  <sect2 id="autocryptdoc-requirements">
    <title>Requirements</title>
    <para>
      Autocrypt requires support for ECC cryptography, and Mutt by
      default will generate ECC keys.  Therefore GnuPG 2.1 or greater
      is required.  Additionally, Mutt's Autocrypt implementation uses
      GPGME and requires at least version 1.8.0.
    </para>
    <para>
      Account and peer information is stored in a sqlite3 database, and
      so Mutt must be configured with the <literal>--with-sqlite3</literal>
      flag when autocrypt is enabled.
    </para>
    <para>
      It is highly recommended Mutt be configured
      <literal>--with-idn</literal> or
      <literal>--with-idn2</literal> so that Autocrypt can properly
      deal with international domain names.
    </para>
    <para>
      While Mutt uses GPGME for Autocrypt, normal keyring operations
      can still be performed via classic mode (i.e. with <link
      linkend="crypt-use-gpgme">$crypt_use_gpgme</link> unset).
      However, to avoid unnecessary prompts, it is recommended gpg not
      be configured in <literal>loopback pinentry</literal> mode, and
      that <link linkend="pgp-use-gpg-agent">$pgp_use_gpg_agent</link>
      remain set (the default).
    </para>
  </sect2>

  <sect2 id="autocryptdoc-init">
    <title>First Run</title>
    <para>
      To enable Autocrypt, set <link
      linkend="autocrypt">$autocrypt</link>, and if desired change the
      value of <link linkend="autocrypt-dir">$autocrypt_dir</link> in
      your muttrc.  The first time Mutt is run after that, you will be
      prompted to create <link
      linkend="autocrypt-dir">$autocrypt_dir</link>.  Mutt will then
      automatically create an sqlite3 database and GPG keyring in that
      directory.  Note since these files should be considered private,
      Mutt will create this directory with mode
      <literal>700</literal>.  If you create the directory manually,
      you should do the same.
    </para>
    <para>
      Mutt recommends keeping the <link
      linkend="autocrypt-dir">$autocrypt_dir</link> directory set
      differently from your GnuPG keyring directory
      (e.g. <literal>~/.gnupg</literal>).  Keys are automatically
      imported into the keyring from <literal>Autocrypt:</literal>
      headers.  Compared to standard <quote>web of trust</quote> keys,
      Autocrypt keys are somewhat ephemeral, and the autocrypt
      database is used to track when keys change or fall out of use.
      Having these keys mixed in with your normal keyring will make it
      more difficult to use features such as <link
      linkend="crypt-opportunistic-encrypt">$crypt_opportunistic_encrypt</link>
      and Autocrypt at the same time.
    </para>
    <para>
      The <link linkend="autocrypt-dir">$autocrypt_dir</link> variable
      is not designed to be changed while Mutt is running.  The
      database is created (if necessary) and connected to during
      startup.  Changing the variable can result in a situation where
      Mutt is looking in one place for the database and a different
      place for the GPG keyring, resulting in strange behavior.
    </para>
    <para>
      Once the directory, keyring, and database are created, Mutt will
      ask whether you would like to create an account.  In order to
      use Autocrypt, each sending address needs an account.  As a
      convenience you can create an account during the first run.  If
      you would like to add additional accounts later, this can be
      done via the <literal>&lt;autocrypt-acct-menu&gt;</literal>
      function in the index, by default bound to <literal>A</literal>.
    </para>
    <para>
      Account creation will first ask you for an email address.  Next,
      it will ask whether you want to create a new key or select an
      existing key.  (Note key selection takes place from the <link
      linkend="autocrypt-dir">$autocrypt_dir</link> keyring, which
      will normally be empty during first run).  Finally, it will ask
      whether this address should prefer encryption or not.  Autocrypt
      1.1 allows automatically enabling encryption if
      <emphasis>both</emphasis> sender and receiver have set
      <quote>prefer encryption</quote>.  Otherwise, you will need to
      manually enable autocrypt encryption in the compose menu.  For
      more details, see the compose menu section below.
    </para>
    <para>
      After optionally creating an account, Mutt will prompt you to
      scan mailboxes for Autocrypt headers.  This step occurs because
      header cached messages are not re-scanned for Autocrypt headers.
      Scanning during this step will temporarily disable the header
      cache while opening each mailbox.  If you wish to do this
      manually later, you can simulate the same thing by unsetting
      <link linkend="header-cache">$header_cache</link> and opening a
      mailbox.
    </para>
    <para>
      A final technical note: the first run process takes place
      between reading the muttrc and opening the initial mailbox.
      Some muttrc files will <link linkend="push">push</link> macros
      to be run after opening the mailbox.  To prevent this from
      interfering with the first run prompts, Mutt disables all macros
      during the first run.
    </para>
  </sect2>

  <sect2 id="autocryptdoc-compose">
    <title>Compose Menu</title>
    <para>
      When enabled, Autocrypt will add a line to the compose menu with
      two fields: <literal>Autocrypt:</literal> and
      <literal>Recommendation:</literal>.
    </para>
    <para>
      The <literal>Autocrypt:</literal> field shows whether the
      message will be encrypted by Autocrypt when sent.  It has two
      values: <literal>Encrypt</literal> and <literal>Off</literal>.
      <literal>Encrypt</literal> can be enabled using the
      <literal>&lt;autocrypt-menu&gt;</literal> function, by default
      bound to <literal>o</literal>.
    </para>
    <para>
      The <literal>Recommendation:</literal> field shows the output of
      the Autocrypt recommendation engine.  This can have one of five
      values:
    </para>
    <itemizedlist>
      <listitem>
        <para>
          <literal>Off</literal> means the engine is disabled.  This
          can happen if the From address doesn't have an autocrypt
          account, or if the account has been manually disabled.
        </para>
      </listitem>
      <listitem>
        <para>
          <literal>No</literal> means one or more recipients are
          missing an autocrypt key, or the key found is unusable
          (i.e. expired, revoked, disabled, invalid, or not usable for
          encryption.)
        </para>
      </listitem>
      <listitem>
        <para>
          <literal>Discouraged</literal> means a key was found for
          every recipient, but the engine is not confident the message
          will be decryptable by the recipient.  This can happen if
          the key hasn't been used recently (compared to their last
          seen email).
        </para>
        <para>
          It can also happen if the key wasn't seen first-hand from
          the sender.  Autocrypt has a feature where recipient keys
          can be included in group-encrypted emails.  This allows you
          to reply to a conversation where you don't have a key
          first-hand from one of the other recipients.  However, those
          keys are not trusted as much as from first-hand emails, so
          the engine warns you with a <literal>Discouraged</literal>
          status.
        </para>
      </listitem>
      <listitem>
        <para>
          <literal>Available</literal> means a key was found for every
          recipient, and the engine believes all keys are recent and
          seen from the recipient first hand.  However, either you or
          one of the recipients chose not to specify <quote>prefer
          encryption</quote>.
        </para>
      </listitem>
      <listitem>
        <para>
          <literal>Yes</literal> is the same as
          <literal>Available</literal>, with the addition that you and
          all recipients have specified <quote>prefer
          encryption</quote>.  This value will automatically enable
          encryption, unless you have manually switched it off or
          enabled regular encryption or signing via the
          <literal>&lt;pgp-menu&gt;</literal>.
        </para>
      </listitem>
    </itemizedlist>
    <para>
      As mentioned above the <literal>&lt;autocrypt-menu&gt;</literal>
      function, by default bound to <literal>o</literal>, can be used
      to change the <literal>Encrypt:</literal> field value.
      <literal>(e)ncrypt</literal> will toggle encryption on.
      <literal>(c)lear</literal> will toggle encryption off.  If
      either of these are chosen, the field will remain in that state
      despite what the <literal>Recommendation:</literal> field shows.
      Lastly, <literal>(a)utomatic</literal> will set the value based
      on the recommendation engine's output.
    </para>
    <para>
      Autocrypt encryption defers to normal encryption or signing.
      <emphasis>Anything</emphasis> that enables normal encryption or
      signing will cause autocrypt encryption to turn off.  The only
      exception is when replying to an autocrypt-encrypted email
      (i.e. an email decrypted from the <link
      linkend="autocrypt-dir">$autocrypt_dir</link> keyring).  Then,
      if <link linkend="autocrypt-reply">$autocrypt_reply</link> is
      <emphasis>set</emphasis>, autocrypt mode will be forced on,
      overriding the settings
      <link linkend="crypt-autosign">$crypt_autosign</link>,
      <link linkend="crypt-autoencrypt">$crypt_autoencrypt</link>,
      <link linkend="crypt-replyencrypt">$crypt_replyencrypt</link>,
      <link linkend="crypt-replysign">$crypt_replysign</link>,
      <link linkend="crypt-replysignencrypted">$crypt_replysignencrypted</link>, and
      <link linkend="crypt-opportunistic-encrypt">$crypt_opportunistic_encrypt</link>.
    </para>
    <para>
      When postponing a message, autocrypt will respect <link
      linkend="postpone-encrypt">$postpone_encrypt</link>, but will
      use the autocrypt account key to encrypt the message.  Be sure
      to set <link linkend="postpone-encrypt">$postpone_encrypt</link>
      to ensure postponed messages marked for autocrypt encryption are
      encrypted.
    </para>
  </sect2>

  <sect2 id="autocryptdoc-acctmgmt">
    <title>Account Management</title>
    <para>
      The Autocrypt Account Menu is available from the index via
      <literal>&lt;autocrypt-acct-menu&gt;</literal>, by default bound
      to <literal>A</literal>.  See <link
      linkend="autocrypt-account-map">Autocrypt Account Menu</link> for the
      list of functions and their default keybindings.
    </para>
    <para>
      In this menu, you can create new accounts, delete accounts,
      toggle an account active/inactive, and toggle the <quote>prefer
      encryption</quote> flag for an account.
    </para>
    <para>
      Deleting an account only removes the account from the database.
      The GPG key is kept, to ensure you still have the ability to
      read past encrypted emails.
    </para>
    <para>
      The Autocrypt 1.1 <quote>Setup Message</quote> feature is not
      available yet, but will be added in the future.
    </para>
  </sect2>

  <sect2 id="autocryptdoc-keyrings">
    <title>Alternative Key and Keyring Strategies</title>
    <para>
      Mutt by default partitions Autocrypt from normal keyring
      encryption/signing.  It does this by using a separate GPG
      keyring (in <link linkend="autocrypt-dir">$autocrypt_dir</link>)
      and creating a new ECC key in that keyring for accounts.  There
      are good reasons for doing this by default.  It keeps random
      keys found inside email headers out of your normal keyring.  ECC
      keys are compact and better suited for email headers.  Autocrypt
      key selection is completely different from <quote>web of
      trust</quote> key selection, based on last-seen rules as opposed
      to trust and validity.  It also allows Mutt to distinguish
      Autocrypt encrypted emails from regular encrypted emails, and
      set the mode appropriately when replying to each type of email.
    </para>
    <para>
      Still, some users may want to use an existing key from their
      normal keyring for Autocrypt too.  There are two ways this can
      be accomplished.  The <emphasis>recommended</emphasis> way is to
      set <link linkend="autocrypt-dir">$autocrypt_dir</link> to your
      normal keyring directory (e.g. <literal>~/.gnupg</literal>).
      During account creation, choosing <quote>(s)elect existing GPG
      key</quote> will then list and allow selecting your existing key
      for the new account.
    </para>
    <para>
     An alternative is to copy your key over to the Autocrypt keyring,
     but there is a severe downside.  Mutt <emphasis>first</emphasis>
     tries to decrypt messages using the Autocrypt keyring, and if
     that fails tries the normal keyring second.  This means all
     encrypted emails to that key will be decrypted, and have
     signatures verified from, the Autocrypt keyring.  Keys signatures
     and web of trust from your normal keyring will no longer show up
     in signatures when decrypting.
    </para>
    <para>
      For that reason, if you want to use an existing key from your
      normal keyring, it is recommended to just set <link
      linkend="autocrypt-dir">$autocrypt_dir</link> to
      <literal>~/.gnupg</literal>.  This allows <quote>web of
      trust</quote> to show an appropriate signature message for
      verified messages.  Autocrypt header keys will be imported into
      your keyring, but if you don't want them mixed you should
      strongly consider using a separate autocrypt key and keyring
      instead.
    </para>
    <para>
      Both methods have a couple additional caveats:
    </para>
    <itemizedlist>
      <listitem>
        <para>
          Replying to an Autocrypt decrypted message by default forces
          Autocrypt mode on.  By sharing the same key, all replies
          will then start in Autocrypt mode, even if a message wasn't
          sent by one of your Autocrypt peers.  <link
          linkend="autocrypt-reply">$autocrypt_reply</link> can be
          <emphasis>unset</emphasis> to allow manual control of the
          mode when replying.
        </para>
      </listitem>
      <listitem>
        <para>
          When Mutt creates an account from a GPG key, it exports the
          public key, base64 encodes it, and stores that value in the
          sqlite3 database.  The value is then used in the Autocrypt
          header added to outgoing emails.  The ECC keys Mutt creates
          don't change, but if you use external keys that expire, when
          you resign to extend the expiration you will need to
          recreate the Autocrypt account using the <link
          linkend="autocryptdoc-acctmgmt">account menu</link>.
          Otherwise the Autocrypt header will contain the old expired
          exported keydata.
        </para>
      </listitem>
    </itemizedlist>
  </sect2>
</sect1>
</chapter>

<chapter id="security">
<title>Security Considerations</title>

<para>
First of all, Mutt contains no security holes included by intention but
may contain unknown security holes. As a consequence, please run Mutt
only with as few permissions as possible. Especially, do not run Mutt as
the super user.
</para>

<para>
When configuring Mutt, there're some points to note about secure setups
so please read this chapter carefully.
</para>

<sect1 id="security-passwords">
<title>Passwords</title>

<para>
Although Mutt can be told the various passwords for accounts, please
never store passwords in configuration files. Besides the fact that the
system's operator can always read them, you could forget to mask it out
when reporting a bug or asking for help via a mailing list. Even worse,
your mail including your password could be archived by internet search
engines, mail-to-news gateways etc. It may already be too late before
you notice your mistake.
</para>

</sect1>

<sect1 id="security-tempfiles">
<title>Temporary Files</title>

<para>
Mutt uses many temporary files for viewing messages, verifying digital
signatures, etc. As long as being used, these files are visible by other
users and maybe even readable in case of misconfiguration.  Also, a
different location for these files may be desired which can be changed
via the <link linkend="tmpdir">$tmpdir</link> variable.
</para>

</sect1>

<sect1 id="security-leaks">
<title>Information Leaks</title>

<sect2 id="security-leaks-mailto">
<title><literal>mailto:</literal>-style Links</title>

<para>
As Mutt be can be set up to be the mail client to handle
<literal>mailto:</literal> style links in websites, there're security
considerations, too. Arbitrary header fields can be embedded in these
links which could override existing header fields or attach arbitrary
files using <link linkend="attach-header">the Attach:
pseudoheader</link>. This may be problematic if the <link
linkend="edit-headers">$edit-headers</link> variable is
<emphasis>unset</emphasis>, i.e. the user doesn't want to see header
fields while editing the message and doesn't pay enough attention to the
compose menu's listing of attachments.
</para>

<para>
For example, following a link like
</para>

<screen>
mailto:joe@host?Attach=~/.gnupg/secring.gpg</screen>

<para>
will send out the user's private gnupg keyring to
<literal>joe@host</literal> if the user doesn't follow the information
on screen carefully enough.
</para>

<para>
To prevent these issues, Mutt by default only accepts the
<literal>Subject</literal> and <literal>Body</literal> headers.
Allowed headers can be adjusted with the
<link linkend="mailto-allow"><command>mailto_allow</command></link> and
<link linkend="mailto-allow"><command>unmailto_allow</command></link> commands.
</para>

</sect2>

</sect1>

<sect1 id="security-external">
<title>External Applications</title>

<para>
Mutt in many places has to rely on external applications or for
convenience supports mechanisms involving external applications.
</para>

<para>
One of these is the <literal>mailcap</literal> mechanism as defined by
RfC1524. Details about a secure use of the mailcap mechanisms is given
in <xref linkend="secure-mailcap"/>.
</para>

<para>
Besides the mailcap mechanism, Mutt uses a number of other external
utilities for operation, for example to provide crypto support, in
backtick expansion in configuration files or format string filters.  The
same security considerations apply for these as for tools involved via
mailcap.
</para>

</sect1>

</chapter>


<chapter id="tuning">
<title>Performance Tuning</title>

<sect1 id="tuning-mailboxes">
<title>Reading and Writing Mailboxes</title>

<para>
Mutt's performance when reading mailboxes can be improved in two ways:
</para>

<orderedlist>

<listitem>
<para>
For remote folders (IMAP and POP) as well as folders using one-file-per
message storage (Maildir and MH), Mutt's performance can be greatly
improved using <link linkend="header-caching">header caching</link>.
using a single database per folder.
</para>
</listitem>

<listitem>
<para>
Mutt provides the <link linkend="read-inc">$read_inc</link> and <link
linkend="write-inc">$write_inc</link> variables to specify at which rate
to update progress counters. If these values are too low, Mutt may spend
more time on updating the progress counter than it spends on actually
reading/writing folders.
</para>

<para>
For example, when opening a maildir folder with a few thousand messages,
the default value for <link linkend="read-inc">$read_inc</link> may be
too low. It can be tuned on a folder-basis using <link
linkend="folder-hook"><command>folder-hook</command>s</link>:
</para>

<screen>
<emphasis role="comment"># use very high $read_inc to speed up reading hcache'd maildirs</emphasis>
folder-hook . 'set read_inc=1000'
<emphasis role="comment"># use lower value for reading slower remote IMAP folders</emphasis>
folder-hook ^imap 'set read_inc=100'
<emphasis role="comment"># use even lower value for reading even slower remote POP folders</emphasis>
folder-hook ^pop 'set read_inc=1'</screen>

</listitem>
</orderedlist>

<para>
These settings work on a per-message basis. However, as messages may
greatly differ in size and certain operations are much faster than
others, even per-folder settings of the increment variables may not be
desirable as they produce either too few or too much progress updates.
Thus, Mutt allows to limit the number of progress updates per second
it'll actually send to the terminal using the <link
linkend="time-inc">$time_inc</link> variable.
</para>

</sect1>

<sect1 id="tuning-messages">
<title>Reading Messages from Remote Folders</title>

<para>
Reading messages from remote folders such as IMAP an POP can be slow
especially for large mailboxes since Mutt only caches a very limited
number of recently viewed messages (usually 10) per session (so that it
will be gone for the next session.)
</para>

<para>
To improve performance and permanently cache whole messages and
headers, please refer to <link linkend="body-caching">body
caching</link> and <link linkend="header-caching">header
caching</link> for details.
</para>

<para>
Additionally, it may be worth trying some of Mutt's experimental
features.  <link linkend="imap-qresync">$imap_qresync</link> (which
requires header caching) can provide a huge speed boost opening
mailboxes if your IMAP server supports it.  <link
linkend="imap-deflate">$imap_deflate</link> enables compression, which
can also noticeably reduce download time for large mailboxes and
messages.
</para>

</sect1>

<sect1 id="tuning-search">
<title>Searching and Limiting</title>

<para>
When searching mailboxes either via a search or a limit action, for some
patterns Mutt distinguishes between regular expression and string
searches. For regular expressions, patterns are prefixed with
<quote>~</quote> and with <quote>=</quote> for string searches.
</para>

<para>
Even though a regular expression search is fast, it's several times
slower than a pure string search which is noticeable especially on large
folders. As a consequence, a string search should be used instead of a
regular expression search if the user already knows enough about the
search pattern.
</para>

<para>
For example, when limiting a large folder to all messages sent to or by
an author, it's much faster to search for the initial part of an e-mail
address via <literal>=Luser@</literal> instead of
<literal>~Luser@</literal>. This is especially true for searching
message bodies since a larger amount of input has to be searched.
</para>

<para>
As for regular expressions, a lower case string search pattern makes
Mutt perform a case-insensitive search except for IMAP (because for IMAP
Mutt performs server-side searches which don't support
case-insensitivity).
</para>

</sect1>

</chapter>

<chapter id="reference">
<title>Reference</title>

<sect1 id="commandline">
<title>Command-Line Options</title>

<para>
Running <literal>mutt</literal> with no arguments will make Mutt attempt
to read your spool mailbox.  However, it is possible to read other
mailboxes and to send messages from the command line as well.
</para>

<table id="tab-commandline-options">
<title>Command line options</title>
<tgroup cols="2">
<thead>
<row><entry>Option</entry><entry>Description</entry></row>
</thead>
<tbody>
<row><entry>-A</entry><entry>expand an alias</entry></row>
<row><entry>-a</entry><entry>attach a file to a message</entry></row>
<row><entry>-b</entry><entry>specify a blind carbon-copy (BCC) address</entry></row>
<row><entry>-c</entry><entry>specify a carbon-copy (Cc) address</entry></row>
<row><entry>-d</entry><entry>log debugging output to ~/.muttdebug0 if mutt was compiled with +DEBUG; it can range from 1-5 and affects verbosity (a value of 2 is recommended)</entry></row>
<row><entry>-D</entry><entry>print the value of all Mutt variables to stdout</entry></row>
<row><entry>-E</entry><entry>edit the draft (-H) or include (-i) file</entry></row>
<row><entry>-e</entry><entry>specify a config command to be run after initialization files are read</entry></row>
<row><entry>-f</entry><entry>specify a mailbox to load</entry></row>
<row><entry>-F</entry><entry>specify an alternate file to read initialization commands</entry></row>
<row><entry>-h</entry><entry>print help on command line options</entry></row>
<row><entry>-H</entry><entry>specify a draft file from which to read a header and body</entry></row>
<row><entry>-i</entry><entry>specify a file to include in a message composition</entry></row>
<row><entry>-m</entry><entry>specify a default mailbox type</entry></row>
<row><entry>-n</entry><entry>do not read the system Muttrc</entry></row>
<row><entry>-p</entry><entry>recall a postponed message</entry></row>
<row><entry>-Q</entry><entry>query a configuration variable</entry></row>
<row><entry>-R</entry><entry>open mailbox in read-only mode</entry></row>
<row><entry>-s</entry><entry>specify a subject (enclose in quotes if it contains spaces)</entry></row>
<row><entry>-v</entry><entry>show version number and compile-time definitions</entry></row>
<row><entry>-x</entry><entry>simulate the mailx(1) compose mode</entry></row>
<row><entry>-y</entry><entry>show a menu containing the files specified by the <command>mailboxes</command> command</entry></row>
<row><entry>-z</entry><entry>exit immediately if there are no messages in the mailbox</entry></row>
<row><entry>-Z</entry><entry>open the first folder with new message, exit immediately if none</entry></row>
</tbody>
</tgroup>
</table>

<para>
To read messages in a mailbox
</para>

<cmdsynopsis>
<command>mutt</command>
<arg choice="opt"><option>-nz</option></arg>
<arg choice="opt"><option>-F</option>
<replaceable>muttrc</replaceable>
</arg>
<arg choice="opt"><option>-m</option>
<replaceable>type</replaceable>
</arg>
<arg choice="opt"><option>-f</option>
<replaceable>mailbox</replaceable>
</arg>
</cmdsynopsis>

<para>
To compose a new message
</para>

<cmdsynopsis>
<command>mutt</command>
<arg choice="opt"><option>-En</option></arg>
<arg choice="opt"><option>-F</option>
<replaceable>muttrc</replaceable>
</arg>
<arg choice="opt"><option>-c</option>
<replaceable>address</replaceable>
</arg>
<arg choice="opt"><option>-Hi</option>
<replaceable>filename</replaceable>
</arg>
<arg choice="opt"><option>-s</option>
<replaceable>subject</replaceable>
</arg>
<arg choice="opt">
<option>-a</option>
<replaceable>file</replaceable>
<arg choice="opt" rep="repeat"/>
--
</arg>
<group choice="plain" rep="repeat">
<arg choice="plain">
<replaceable>address</replaceable>
</arg>
<arg choice="plain">
<replaceable>mailto_url</replaceable>
</arg>
</group>
</cmdsynopsis>

<para>
Mutt also supports a <quote>batch</quote> mode to send prepared
messages.  Simply redirect input from the file you wish to send.  For
example,
</para>

<screen>
mutt -s "data set for run #2" professor@bigschool.edu &lt; ~/run2.dat</screen>

<para>
will send a message to
<literal>&lt;professor@bigschool.edu&gt;</literal> with a subject of
<quote>data set for run #2</quote>.  In the body of the message will be
the contents of the file <quote>~/run2.dat</quote>.
</para>

<para>
An include file passed with <literal>-i</literal> will be used as the
body of the message.  When combined with <literal>-E</literal>, the
include file will be directly edited during message composition.  The
file will be modified regardless of whether the message is sent or
aborted.
</para>

<para>
A draft file passed with <literal>-H</literal> will be used as the
initial header and body for the message.  Multipart messages can be
used as a draft file.  When combined with <literal>-E</literal>, the
draft file will be updated to the final state of the message after
composition, regardless of whether the message is sent, aborted, or
even postponed.  Note that if the message is sent encrypted or signed,
the draft file will be saved that way too.
</para>

<para>
All files passed with <literal>-a</literal> <emphasis>file</emphasis>
will be attached as a MIME part to the message. To attach a single or
several files, use <quote>--</quote> to separate files and recipient
addresses:
</para>

<screen>
mutt -a image.png -- some@one.org</screen>

<para>
or
</para>

<screen>
mutt -a *.png -- some@one.org</screen>

<note>
<para>
The <literal>-a</literal> option must be last in the option list.
</para>
</note>

<para>
In addition to accepting a list of email addresses, Mutt also accepts a URL with
the <literal>mailto:</literal> schema as specified in RFC2368.  This is useful
when configuring a web browser to launch Mutt when clicking on mailto links.
</para>

<screen>
mutt mailto:some@one.org?subject=test&amp;cc=other@one.org</screen>

</sect1>

<sect1 id="commands">
<title>Configuration Commands</title>

<para>
The following are the commands understood by Mutt:
</para>

<itemizedlist>

<listitem>
<cmdsynopsis>
<command><link linkend="account-hook">account-hook</link></command>
<arg choice="plain">
<replaceable>regexp</replaceable>
<replaceable>command</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="alias">alias</link></command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable class="parameter">name</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">key</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">address</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">address</replaceable>
</arg>

<command><link linkend="alias">unalias</link></command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable>name</replaceable>
</arg>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">key</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="alternates">alternates</link></command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable>name</replaceable>
</arg>
<arg choice="plain">
<replaceable>regexp</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable>regexp</replaceable>
</arg>

<command><link linkend="alternates">unalternates</link></command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable>name</replaceable>
</arg>
<group choice="req">
<arg choice="plain">
<replaceable>*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable>regexp</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="alternative-order">alternative_order</link></command>
<arg choice="plain">
<replaceable>mimetype</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable>mimetype</replaceable>
</arg>

<command><link linkend="alternative-order">unalternative_order</link></command>
<group choice="req">
<arg choice="plain">
<replaceable>*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable>mimetype</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="attachments">attachments</link></command>
<arg choice="plain">
<replaceable>{ + | - }disposition</replaceable>
</arg>
<arg choice="plain">
<replaceable>mime-type</replaceable>
</arg>

<command><link linkend="attachments">unattachments</link></command>
<arg choice="plain">
<replaceable>{ + | - }disposition</replaceable>
</arg>
<arg choice="plain">
<replaceable>mime-type</replaceable>
</arg>

<command><link linkend="attachments">attachments</link></command>
<arg choice="plain"><option>?</option></arg>

<command><link linkend="attachments">unattachments</link></command>
<arg choice="plain"><option>*</option></arg>

</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="auto-view">auto_view</link></command>
<arg choice="plain">
<replaceable>mimetype</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable>mimetype</replaceable>
</arg>

<command><link linkend="auto-view">unauto_view</link></command>
<group choice="req">
<arg choice="plain">
<replaceable>*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable>mimetype</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="bind">bind</link></command>
<arg choice="plain">
<replaceable class="parameter">map</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">key</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">function</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="cd">cd</link></command>
<arg choice="plain">
<replaceable class="parameter">directory</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="charset-hook">charset-hook</link></command>
<arg choice="plain">
<replaceable class="parameter">alias</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">charset</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="charset-hook">iconv-hook</link></command>
<arg choice="plain">
<replaceable class="parameter">charset</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">local-charset</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="color">color</link></command>
<arg choice="plain">
<replaceable class="parameter">object</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">attribute</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">foreground</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">background</replaceable>
</arg>

<command><link linkend="color">color</link></command>
<group choice="req">
<arg choice="plain">
<option>header</option>
</arg>
<arg choice="plain">
<option>body</option>
</arg>
</group>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">attribute</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">foreground</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">background</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">regexp</replaceable>
</arg>

<command><link linkend="color">color</link></command>
<arg choice="plain">
<option>index</option>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">attribute</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">foreground</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">background</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>

<command><link linkend="color">color</link></command>
<arg choice="plain">
<option>compose</option>
</arg>
<arg choice="plain">
<replaceable class="parameter">composeobject</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">attribute</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">foreground</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">background</replaceable>
</arg>

<command><link linkend="color">uncolor</link></command>
<group choice="req">
<arg choice="plain">
<option>index</option>
</arg>
<arg choice="plain">
<option>header</option>
</arg>
<arg choice="plain">
<option>body</option>
</arg>
</group>
<group choice="req">
<arg choice="plain">
<replaceable>*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable>pattern</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="crypt-hook">crypt-hook</link></command>
<arg choice="plain">
<replaceable class="parameter">regexp</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">keyid</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="echo">echo</link></command>
<arg choice="plain">
<replaceable class="parameter">message</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="exec">exec</link></command>
<arg choice="plain">
<replaceable class="parameter">function</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">function</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="fcc-hook">fcc-hook</link></command>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">mailbox</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="fcc-save-hook">fcc-save-hook</link></command>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">mailbox</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="folder-hook">folder-hook</link></command>
<arg choice="plain">
<replaceable class="parameter">[!]regexp</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">command</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="addrgroup">group</link></command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable class="parameter">name</replaceable>
</arg>
<group choice="req">
<arg choice="plain" rep="repeat">
<option>-rx</option>
<replaceable class="parameter">expr</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<option>-addr</option>
<replaceable class="parameter">expr</replaceable>
</arg>
</group>

<command><link linkend="addrgroup">ungroup</link></command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable class="parameter">name</replaceable>
</arg>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<option>-rx</option>
<replaceable class="parameter">expr</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<option>-addr</option>
<replaceable class="parameter">expr</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="hdr-order">hdr_order</link></command>
<arg choice="plain">
<replaceable class="parameter">header</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">header</replaceable>
</arg>

<command><link linkend="hdr-order">unhdr_order</link></command>
<group choice="req">
<arg choice="plain">
<replaceable>*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable>header</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="ignore">ignore</link></command>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">pattern</replaceable>
</arg>

<command><link linkend="ignore">unignore</link></command>
<group choice="req">
<arg choice="plain">
<replaceable>*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable>pattern</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="index-format-hook">index-format-hook</link></command>
<arg choice="plain">
<replaceable class="parameter">name</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">format-string</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="lists">lists</link></command>
<arg>
<option>-group</option>
<replaceable class="parameter">name</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">regexp</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">regexp</replaceable>
</arg>

<command><link linkend="lists">unlists</link></command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable>name</replaceable>
</arg>
<group choice="req">
<arg choice="plain">
<replaceable>*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable>regexp</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="macro">macro</link></command>
<arg choice="plain">
<replaceable class="parameter">menu</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">key</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">sequence</replaceable>
</arg>
<arg choice="opt">
<replaceable class="parameter">description</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="mailboxes">mailboxes</link></command>
<arg choice="opt">
  <group choice="opt">
    <arg choice="plain">
      <option>-poll</option>
    </arg>
    <arg choice="plain">
      <option>-nopoll</option>
    </arg>
  </group>
  <group choice="opt">
    <arg choice="plain">
      <option>-label</option>
      <replaceable>label</replaceable>
    </arg>
    <arg choice="plain">
      <option>-nolabel</option>
    </arg>
  </group>
  <arg choice="plain">
    <replaceable class="parameter">mailbox</replaceable>
  </arg>
</arg>
<arg choice="opt" rep="repeat"></arg>

<command><link linkend="mailboxes">unmailboxes</link></command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">mailbox</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="mailto-allow">mailto_allow</link></command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">header-field</replaceable>
</arg>
</group>

<command><link linkend="mailto-allow">unmailto_allow</link></command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">header-field</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="mbox-hook">mbox-hook</link></command>
<arg choice="plain">
<replaceable class="parameter">[!]regexp</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">mailbox</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="message-hook">message-hook</link></command>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">command</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="mime-lookup">mime_lookup</link></command>
<arg choice="plain">
<replaceable>mimetype</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable>mimetype</replaceable>
</arg>

<command><link linkend="mime-lookup">unmime_lookup</link></command>
<group choice="req">
<arg choice="plain">
<replaceable>*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable>mimetype</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="mono">mono</link></command>
<arg choice="plain">
<replaceable class="parameter">object</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">attribute</replaceable>
</arg>

<command><link linkend="mono">mono</link></command>
<group choice="req">
<arg choice="plain">
<option>header</option>
</arg>
<arg choice="plain">
<option>body</option>
</arg>
</group>
<arg choice="plain">
<replaceable class="parameter">attribute</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">regexp</replaceable>
</arg>

<command><link linkend="mono">mono</link></command>
<arg choice="plain">
<option>index</option>
</arg>
<arg choice="plain">
<replaceable class="parameter">attribute</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>

<command><link linkend="mono">mono</link></command>
<arg choice="plain">
<option>compose</option>
</arg>
<arg choice="plain">
<replaceable class="parameter">composeobject</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">attribute</replaceable>
</arg>

<command><link linkend="mono">unmono</link></command>
<group choice="req">
<arg choice="plain">
<option>index</option>
</arg>
<arg choice="plain">
<option>header</option>
</arg>
<arg choice="plain">
<option>body</option>
</arg>
</group>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">pattern</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="my-hdr">my_hdr</link></command>
<arg choice="plain">
<replaceable class="parameter">string</replaceable>
</arg>

<command><link linkend="my-hdr">unmy_hdr</link></command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">field</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="push">push</link></command>
<arg choice="plain">
<replaceable class="parameter">string</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="reply-hook">reply-hook</link></command>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">command</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="run">run</link></command>
<arg choice="plain">
<replaceable class="parameter">MuttLisp</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="save-hook">save-hook</link></command>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">mailbox</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="score-command">score</link></command>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">value</replaceable>
</arg>

<command><link linkend="score-command">unscore</link></command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">pattern</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="send-hook">send-hook</link></command>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">command</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="send2-hook">send2-hook</link></command>
<arg choice="plain">
<replaceable class="parameter">[!]pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">command</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="set">set</link></command>
<group choice="req">
<arg choice="plain">
<group choice="opt">
<arg choice="plain"><option>no</option></arg>
<arg choice="plain"><option>inv</option></arg>
</group>
<replaceable class="parameter">variable</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">variable=value</replaceable>
</arg>
</group>
<arg choice="opt" rep="repeat"></arg>

<command><link linkend="set">toggle</link></command>
<arg choice="plain">
<replaceable class="parameter">variable</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">variable</replaceable>
</arg>

<command><link linkend="set">unset</link></command>
<arg choice="plain">
<replaceable class="parameter">variable</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">variable</replaceable>
</arg>

<command><link linkend="set">reset</link></command>
<arg choice="plain">
<replaceable class="parameter">variable</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">variable</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
  <cmdsynopsis>
    <command><link linkend="setenv">setenv</link></command>
    <arg choice="plain">
      <replaceable class="parameter">[?]variable</replaceable>
    </arg>
    <arg choice="opt">
      <replaceable class="parameter">value</replaceable>
    </arg>

    <command><link linkend="setenv">unsetenv</link></command>
    <arg choice="plain">
      <replaceable class="parameter">variable</replaceable>
    </arg>
  </cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="sidebar-whitelist">sidebar_whitelist</link></command>
<arg choice="plain">
<replaceable class="parameter">mailbox</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">mailbox</replaceable>
</arg>

<command><link linkend="sidebar-whitelist">unsidebar_whitelist</link></command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">mailbox</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="source">source</link></command>
<arg choice="plain">
<replaceable class="parameter">filename</replaceable>
</arg>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="spam">spam</link></command>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">format</replaceable>
</arg>

<command><link linkend="spam">nospam</link></command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="display-munging">subjectrx</link></command>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">replacement</replaceable>
</arg>

<command><link linkend="display-munging">unsubjectrx</link></command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">pattern</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="subscribe">subscribe</link></command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable class="parameter">name</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">regexp</replaceable>
</arg>
<arg choice="opt" rep="repeat">
<replaceable class="parameter">regexp</replaceable>
</arg>

<command><link linkend="subscribe">unsubscribe</link></command>
<arg choice="opt" rep="repeat">
<option>-group</option>
<replaceable>name</replaceable>
</arg>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain" rep="repeat">
<replaceable class="parameter">regexp</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

<listitem>
<cmdsynopsis>
<command><link linkend="unhook">unhook</link></command>
<group choice="req">
<arg choice="plain">
<replaceable class="parameter">*</replaceable>
</arg>
<arg choice="plain">
<replaceable class="parameter">hook-type</replaceable>
</arg>
</group>
</cmdsynopsis>
</listitem>

</itemizedlist>

</sect1>

<sect1 id="variables">
<title>Configuration Variables</title>
