The Mutt E-Mail Client

The official homepage can be found at http://www.mutt.org/.

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

Mutt releases can be downloaded from ftp://ftp.mutt.org/mutt/. For a list of mirror sites, please refer to http://www.mutt.org/download.html.

For nightly tarballs and version control access, please refer to the Mutt development site.

There are various ways to contribute to the Mutt project.

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.

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.

For contributing code patches for new features and bug fixes, please refer to the developer pages at http://dev.mutt.org/ for more details.

This section lists typographical conventions followed throughout this manual. See table Table 1.1, “Typographical conventions for special terms” for typographical conventions for special terms.

Examples are presented as:

mutt -v

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

Mutt is Copyright © 1996-2009 Michael R. Elkins <me@mutt.org> and others.

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.

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.

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.

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 “index” menu (listing all messages of the currently opened folder) or the “alias” menu (allowing you to select recipients from a list). Examples for page-based menus are the “pager” (showing one message at a time) or the “help” menu listing all available key bindings.

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.

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.

Because Mutt allows for customizing almost all key bindings, there are so-called “functions” 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.

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 “tagged” 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 and and or 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.

Mutt supports a “hook” 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 behaviour including managing multiple identities, customizing the display for a folder or even implementing auto-archiving based on a per-folder basis and much more.

Besides an interactive mode, Mutt can also be used as a command-line tool only send messages. It also supports a mailx(1)-compatible interface, see Table 9.1, “Command line options” for a complete list of command-line options.

The most important navigation keys common to line- or entry-based menus are shown in Table 2.1, “Most common navigation keys in entry-based menus” and in Table 2.2, “Most common navigation keys in page-based menus” for page-based menus.

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 “index” menu in Mutt. The second mode is the display of the message contents. This is called the “pager.”

The next few sections describe the functions provided in each of these modes.

\e[Ps;Ps;..Ps;m

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 <bounce> function and forwarding using the <forward> function bound to “b” and “f” respectively.

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 $mime_forward variable. Decoding of attachments, like in the pager, can be controlled by the $forward_decode and $mime_forward_decode variables, respectively. The desired forwarding format may depend on the content, therefore $mime_forward is a quadoption which, for example, can be set to “ask-no”.

The inclusion of headers is controlled by the current setting of the $weed variable, unless $mime_forward is set.

Editing the message to forward follows the same procedure as sending or replying to a message does.

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

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

See also the $postpone quad-option.

While the default configuration (or “preferences”) 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 “system” configuration file (defaults set by your local system administrator), unless the “-n” command line option is specified. This file is typically /usr/local/share/mutt/Muttrc or /etc/Muttrc. Mutt will next look for a file named .muttrc in your home directory. If this file does not exist and your home directory has a subdirectory named .mutt, Mutt tries to load a file named .mutt/muttrc.

.muttrc is the file where you will usually place your commands to configure Mutt.

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 Muttrc-0.88 file in the system configuration directory, and you are running version 0.88 of Mutt, this file will be sourced instead of the Muttrc file. The same is true of the user configuration file, if you have a file .muttrc-0.88.6 in your home directory, when you run Mutt version 0.88.6, it will source this file instead of the default .muttrc file. The version number is the same which is visible using the “-v” command line switch or using the show-version key (default: V) from the index menu.

An initialization file consists of a series of commands. Each line of the file may contain one or more commands. When multiple commands are used, they must be separated by a semicolon (“;”).

set realname='Mutt user' ; ignore x-

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

my_hdr X-Disclaimer: Why are you listening to me? # This is a comment

Single quotes (“'”) and double quotes (“"”) 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 not for single quotes.

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

set realname="Michael \"MuttDude\" Elkins"

“\\” means to insert a literal “\” into the line. “\n” and “\r” have their usual C meanings of linefeed and carriage-return, respectively.

A “\” at the end of a line can be used to split commands over multiple lines as it “escapes” 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.

set status_format="some very \
long value split \
over several lines"

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 Example 3.5, “Using external command's output in configuration files”, the output of the Unix command “uname -a” 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.

my_hdr X-Operating-System: `uname -a`

Both environment variables and Mutt variables can be accessed by prepending “$” to the name of the variable. For example,

set record=+sent_on_$HOSTNAME

will cause Mutt to save outgoing messages to a folder named “sent_on_kremvax” if the environment variable $HOSTNAME is set to “kremvax.” (See $record for details.)

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.

The commands understood by Mutt are explained in the next paragraphs. For a complete list, see the command reference.

All configuration files are expected to be in the current locale as specified by the $charset 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 $config_charset variable should be used: all lines starting with the next are recoded from $config_charset to $charset.

This mechanism should be avoided if possible as it has the following implications:

Usage:

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

These address groups can also be created implicitly by the alias, lists, subscribe and alternates commands by specifying the optional -group option.

Once defined, these address groups can be used in patterns to search for and limit the display to messages matching a group.

ungroup is used to remove addresses or regular expressions from the specified group or groups. The syntax is similar to the group command, however the special character * can be used to empty a group of all of its contents.

Usage:

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

The optional -group argument to alias causes the aliased address(es) to be added to the named group.

To remove an alias or aliases (“*” means all aliases):

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

Unlike other mailers, Mutt doesn't require aliases to be defined in a special file. The alias command can appear anywhere in a configuration file, as long as this file is sourced. Consequently, you can have multiple alias files, or you can have all aliases defined in your .muttrc.

On the other hand, the <create-alias> function can use only one file, the one pointed to by the $alias_file variable (which is ˜/.muttrc 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 source this file too.

source /usr/local/share/Mutt.aliases
source ~/.mail_aliases
set alias_file=~/.mail_aliases

To use aliases, you merely use the alias at any place in Mutt where Mutt prompts for addresses, such as the To: or Cc: prompt. You can also enter aliases in your editor at the appropriate headers if you have the $edit_headers variable set.

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.

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

Usage:

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

map 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:

key is the key (or key sequence) you wish to bind. To specify a control character, use the sequence \Cx, where x is the letter of the control character (for example, to specify control-A use “\Ca”). Note that the case of x as well as \C is ignored, so that \CA, \Ca, \cA and \ca are all equivalent. An alternative form is to specify the key as a three digit octal number prefixed with a “\” (for example \177 is equivalent to \c?). In addition, key may be a symbolic name as shown in Table 3.1, “Symbolic key names”.

key does not need to be enclosed in quotes unless it contains a space (“ ”) or semi-colon (“;”).

function specifies which action to take when key is pressed. For a complete list of functions, see the reference. The special function <noop> unbinds the specified key sequence.

Usage:

The charset-hook 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.

The iconv-hook 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.

Usage:

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

folder-hook mutt "set sort=threads"

The following example will set the sort variable to date-sent for all folders but to threads for all folders containing “mutt” in their name.

folder-hook . "set sort=date-sent"
folder-hook mutt "set sort=threads"

Usage:

Macros are useful when you would like a single key to perform a series of actions. When you press key in menu menu, Mutt will behave as if you had typed sequence. 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.

menu is the map 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.

key and sequence are expanded by the same rules as the key bindings with some additions. The first is that control characters in sequence can also be specified as ^x. In order to get a caret (“^”) you need to use ^^. Secondly, to specify a certain key such as up or to invoke a function directly, you can use the format <key name> and <function name>. For a listing of key names see the section on key bindings. Functions are listed in the reference.

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).

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

Usage:

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 and a background color (it is not possible to only specify one or the other).

header and body match regexp in the header/body of a message, index matches pattern (see Section 2, “Patterns: Searching, Limiting and Tagging”) in the message index.

object can be one of:

foreground and background can be one of the following:

foreground can optionally be prefixed with the keyword bright to make the foreground color boldfaced (e.g., brightred).

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

set COLORFGBG="green;black"
export COLORFGBG

Mutt also recognizes the keywords color0, color1, …, colorN-1 (N 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 color2 for your xterm), since color names may then lose their normal meaning.

If your terminal does not support color, it is still possible change the video attributes through the use of the “mono” command. Usage:

For object, see the color command. attribute can be one of the following:

Usage:

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 — responding to yourself won't make much sense in many cases. (See $reply_to.)

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 alternates command: It takes a list of regular expressions, each of which can identify an address under which you receive e-mail.

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:

alternates user@example

Mutt will consider “some-user@example” as being your address, too which may not be desired. As a solution, in such cases addresses should be specified as:

alternates '^user@example$'

The -group flag causes all of the subsequent regular expressions to be added to the named group.

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

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

Usage:

Mutt has a few nice features for handling mailing lists. 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 mailto: links in the common List-Post: header which has the same effect as specifying the list address via the lists command (except the group feature). Once you have done this, the <list-reply> function will work for all known lists. Additionally, when you send a message to a subscribed list, Mutt will add a Mail-Followup-To header to tell other users' mail user agents not to send copies of replies to your personal address.

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 list command. To mark it as subscribed, use subscribe.

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

subscribe [0-9]*.*@bugs.debian.org

as it's often, it's sufficient to just give a portion of the list's e-mail address.

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

The -group flag adds all of the subsequent regular expressions to the named group.

The “unlists” command is used to remove a token from the list of known and subscribed mailing-lists. Use “unlists *” to remove all tokens.

To remove a mailing list from the list of subscribed mailing lists, but keep it on the list of known mailing lists, use unsubscribe.

Usage:

This command is used to move read messages from a specified mailbox to a different mailbox automatically when you quit or change folders. pattern is a regular expression specifying the mailbox to treat as a “spool” mailbox and mailbox specifies where mail should be saved when read.

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

Usage:

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

folder can either be a local file or directory (Mbox/Mmdf or Maildir/Mh). If Mutt was built with POP and/or IMAP support, folder can also be a POP/IMAP folder URL. The URL syntax is described in Section 1.2, “URL Syntax”, POP and IMAP are described in Section 3, “POP3 Support” and Section 4, “IMAP Support” respectively.

Mutt provides a number of advanced features for handling (possibly many) folders and new mail within them, please refer to Section 9, “Handling multiple folders” for details (including in what situations and how often Mutt checks for new mail).

The “unmailboxes” command is used to remove a token from the list of folders which receive mail. Use “unmailboxes *” to remove all tokens.

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 biff or frm 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.

In cases where new mail detection for Mbox or Mmdf folders appears to be unreliable, the $check_mbox_size 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.

Usage:

The my_hdr command allows you to create your own header fields which will be added to every message you send and appear in the editor if $edit_headers is set.

For example, if you would like to add an “Organization:” header field to all of your outgoing messages, you can put the command something like shown in Example 3.11, “Defining custom headers” in your .muttrc.

my_hdr Organization: A Really Big Company, Anytown, USA

If you would like to add a header field to a single message, you should either set the $edit_headers variable, or use the <edit-headers> function (default: “E”) in the compose menu so that you can edit the header of your message along with the body.

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

unmy_hdr to cc

Usage:

This command is used to override the default mailbox used when saving messages. mailbox will be used as the default if the message matches pattern, see Message Matching in Hooks for information on the exact format.

To provide more flexibility and good defaults, Mutt applies the expandos of $index_format to mailbox after it was expanded.

# default: save all to ~/Mail/<author name>
save-hook . ~/Mail/%F

# save from me@turing.cs.hmc.edu and me@cs.hmc.edu to $folder/elkins
save-hook me@(turing\\.)?cs\\.hmc\\.edu$ +elkins

# save from aol.com to $folder/spam
save-hook aol\\.com$ +spam

Also see the fcc-save-hook command.

Usage:

This command is used to save outgoing mail in a mailbox other than $record. Mutt searches the initial list of message recipients for the first matching regexp and uses mailbox as the default Fcc: mailbox. If no match is found the message will be saved to $record mailbox.

To provide more flexibility and good defaults, Mutt applies the expandos of $index_format to mailbox after it was expanded.

See Message Matching in Hooks for information on the exact format of pattern.

fcc-hook [@.]aol\\.com$ +spammers

...will save a copy of all messages going to the aol.com domain to the `+spammers' mailbox by default. Also see the fcc-save-hook command.

Usage:

This command is a shortcut, equivalent to doing both a fcc-hook and a save-hook with its arguments, including %-expansion on mailbox according to $index_format.

Usage:

These commands can be used to execute arbitrary configuration commands based upon recipients of the message. pattern is used to match the message, see Message Matching in Hooks for details. command is executed when pattern matches.

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

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

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

Example: send-hook mutt "set mime_forward signature=''"

Another typical use for this command is to change the values of the $attribution, $signature and $locale variables in order to change the language of the attributions and signatures based upon the recipients.

Usage:

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

See Message Matching in Hooks for information on the exact format of pattern.

Example:

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

Usage:

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 crypt-hook 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.

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

Usage:

This command adds the named string to the keyboard buffer. The string may contain control characters, key names and function names like the sequence string in the macro command. You may use it to automatically run a sequence of commands at startup, or when entering certain folders. For example, Example 3.13, “Embedding push in folder-hook” shows how to automatically collapse all threads when entering a folder.

folder-hook . 'push <collapse-all>'

Usage:

This command can be used to execute any function. Functions are listed in the function reference. “execfunction” is equivalent to “push <function>”.

Usage:

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

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

Usage:

Mutt has generalized support for external spam-scoring filters. By defining your spam patterns with the spam and nospam commands, you can limit, search, and sort 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 %H selector in the $index_format variable. (Tip: try %?H?[%H] ? to display spam tags only when they are defined for a given message.)

Your first step is to define your external filter's spam patterns using the spam command. pattern 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 “spam tag” or “spam attribute” (unless it also matches a nospam pattern — see below.) The appearance of this attribute is entirely up to you, and is governed by the format parameter. format can be any static text, but it also can include back-references from the pattern expression. (A regular expression “back-reference” refers to a sub-expression contained within parentheses.) %1 is replaced with the first back-reference in the regex, %2 with the second, etc.

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, $imap_headers may need to be adjusted.

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

For example, suppose one uses DCC, SpamAssassin, and PureMessage, then the configuration might look like in Example 3.14, “Configuring spam detection”.

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=", "

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

If the $spam_separator variable is unset, then each spam pattern match supersedes the previous one. Instead of getting joined format strings, you'll get only the last one to match.

The spam tag is what will be displayed in the index when you use %H in the $index_format variable. It's also the string that the ˜H pattern-matching expression matches against for <search> and <limit> functions. And it's what sorting by spam attribute will use as a sort key.

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.

Generally, when you sort by spam tag, Mutt will sort lexically — 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 sort -n.) A message with no spam attributes at all — that is, one that didn't match any of your spam patterns — is sorted at lowest priority. Numbers are sorted next, beginning with 0 and ranging upward. Finally, non-numeric strings are sorted, with “a” taking lower priority than “z”. 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.

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

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

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

spam "^From: .*MAILER-DAEMON"       "999"

Usage:

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

If the filename begins with a tilde (“˜”), it will be expanded to the path of your home directory.

If the filename ends with a vertical bar (“|”), then filename is considered to be an executable program from which to read input (eg. source ˜/bin/myscript|).

Usage: ifdef item command

This command allows to test if a feature has been compiled in, before actually executing the command. Item can be either the name of a function, variable, or command. Example:

ifdef imap_keepalive 'source ~/.mutt/imap_setup'

Usage:

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

All string patterns in Mutt including those in more complex patterns must be specified using regular expressions (regexp) in the “POSIX extended” 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.

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

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.

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.

The period “.” matches any single character. The caret “^” and the dollar sign “$” are metacharacters that respectively match the empty string at the beginning and end of a line.

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

Certain named classes of characters are predefined. Character classes consist of “[:”, a keyword denoting the class, and “:]”. The following classes are defined by the POSIX standard in Table 4.1, “POSIX regular expression character classes”

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

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:

A regular expression matching a single character may be followed by one of several repetition operators described in Table 4.2, “Regular expression repetition operators”.

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

Two regular expressions may be joined by the infix operator “|”; the resulting regular expression matches any string matching either subexpression.

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.

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.

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 <tag-pattern> function, which is bound to “shift-T” by default. Or you can select individual messages by hand using the <tag-message> function, which is bound to “t” by default. See patterns for Mutt's pattern matching syntax.

Once you have tagged the desired messages, you can use the “tag-prefix” operator, which is the “;” (semicolon) key by default. When the “tag-prefix” operator is used, the next operation will be applied to all tagged messages if that operation can be used in that manner. If the $auto_tag variable is set, the next operation applies to the tagged messages automatically, without requiring the “tag-prefix”.

In macros or push commands, you can use the <tag-prefix-cond> operator. If there are no tagged messages, Mutt will “eat” the rest of the macro to abort it's execution. Mutt will stop “eating” the macro when it encounters the <end-cond> operator; after this operator the rest of the macro will be executed as normal.

A hook 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 hook consists of a regular expression or pattern along with a configuration option/command. See:

for specific details on each type of hook available.

send-hook . 'unmy_hdr From:'
send-hook ~C'^b@b\.b$' my_hdr from: c@c.c

In Example 4.3, “Specifying a “default” hook”, by default the value of $from and $realname is not overridden. When sending messages either To: or Cc: to <b@b.b>, the From: header is changed to <c@c.c>.

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

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 $query_command variable, you specify the wrapper command to use. For example:

set query_command = "mutt_ldap_query.pl '%s'"

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.

An example multiple response output:

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

There are two mechanisms for accessing the query function of Mutt. One is to do a query from the index menu using the <query> 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.

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 <complete-query> 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.

Mutt supports reading and writing of four different local mailbox formats: mbox, MMDF, MH and Maildir. The mailbox type is autodetected, so there is no need to use a flag for different mailbox types. When creating new mailboxes, Mutt uses the default specified with the $mbox_type variable. A short description of the formats follows.

mbox. 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:

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

to denote the start of a new message (this is often referred to as the “From_” 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.

MMDF. This is a variant of the mbox format. Each message is surrounded by lines containing “^A^A^A^A” (four 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).

MH. A radical departure from mbox and MMDF, 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 (“,”) prepended to the filename. Mutt detects this type of mailbox by looking for either .mh_sequences or .xmhcache 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 Section 7.1, “Header Caching” to greatly speed this process up). Depending on the environment, MH is not very disk-space efficient.

Maildir. The newest of the mailbox formats, used by the Qmail MTA (a replacement for sendmail). Similar to MH, except that it adds three subdirectories of the mailbox: tmp, new and cur. 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.

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.

For example, to store a copy of outgoing messages in the folder they were composed in, a folder-hook can be used to set $record:

folder-hook . 'set record=^'

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 lists and subscribe commands in your .muttrc.

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 index menu display. This is useful to distinguish between personal and list mail in the same mailbox. In the $index_format variable, the expando “%L” will print the string “To <list>” when “list” appears in the “To” field, and “Cc <list>” when it appears in the “Cc” field (otherwise it prints the name of the author).

Often times the “To” and “Cc” 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 <list-reply> function, which by default is bound to “L” in the index menu and pager, helps reduce the clutter by only replying to the known mailing list addresses instead of all recipients (except as specified by Mail-Followup-To, see below).

Mutt also supports the Mail-Followup-To header. When you send a message to a list of recipients which includes one or several subscribed mailing lists, and if the $followup_to option is set, Mutt will generate a Mail-Followup-To header which contains all the recipients to whom you send this message, but not your address. This indicates that group-replies or list-replies (also known as “followups”) 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.

Conversely, when group-replying or list-replying to a message which has a Mail-Followup-To header, Mutt will respect this header if the $honor_followup_to configuration variable is set. Using list-reply 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 Mail-Followup-To.

The other method some mailing list admins use is to generate a “Reply-To” 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 “Reply-To” field. Mutt uses the $reply_to variable to help decide which address to use. If set to ask-yes or ask-no, you will be prompted as to whether or not you would like to use the address given in the “Reply-To” field, or reply directly to the address given in the “From” field. When set to yes, the “Reply-To” field will be used when present.

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

Lastly, Mutt has the ability to sort the mailbox into threads. 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.

Mutt supports setups with multiple folders, allowing all of them to be monitored for new mail (see Section 14, “Monitoring Incoming Mail” for details).

When in the index menu and being idle (also see $timeout), Mutt periodically checks for new mail in all folders which have been configured via the mailboxes command. The interval depends on the folder type: for local/IMAP folders it consults $mail_check and $pop_checkinterval for POP folders.

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

For the pager, index and directory browser menus, Mutt contains the <buffy-list> function (bound to “.” by default) which will print a list of folders with new mail in the command line at the bottom of the screen.

For the index, by default Mutt displays the number of mailboxes with new mail in the status bar, please refer to the $status_format variable for details.

When changing folders, Mutt fills the prompt with the first folder from the mailboxes list containing new mail (if any), pressing space will cycle through folders with new mail.

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.

RFC1894 defines a set of MIME content types for relaying information about the status of electronic mail messages. These can be thought of as “return receipts.”

To support DSN, there are two variables. $dsn_notify is used to request receipts for different results (such as failed message, message delivered, etc.). $dsn_return requests how much of your message should be returned with the receipt (headers or full message).

When using $sendmail 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.

For SMTP delivery using $smtp_url, it depends on the capabilities announced by the server whether Mutt will attempt to request DSN or not.

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 ftp://ftp.mutt.org/mutt/contrib/ and the configuration commands:

macro index \cb |urlview\n
macro pager \cb |urlview\n

This section documents various features that fit nowhere else.

There are three areas/menus in Mutt which deal with MIME, they are the pager (while viewing a message), the attachment menu and the compose menu.

[-- Attachment #1: Description --]
[-- Type: text/plain, Encoding: 7bit, Size: 10000 --]

[-- image/gif is unsupported (use 'v' to view this part) --]

- 1 [text/plain, 7bit, 1K]           /tmp/mutt-euler-8082-0 <no description>
  2 [applica/x-gunzip, base64, 422K] ~/src/mutt-0.85.tar.gz <no description>

When you add an attachment to your mail message, Mutt searches your personal mime.types file at ${HOME}/.mime.types, and then the system mime.types file at /usr/local/share/mutt/mime.types or /etc/mime.types

The mime.types file consist of lines containing a MIME type and a space separated list of extensions. For example:

application/postscript          ps eps
application/pgp                 pgp
audio/x-aiff                    aif aifc aiff

A sample mime.types file comes with the Mutt distribution, and should contain most of the MIME types you are likely to use.

If Mutt can not determine the mime type by the extension of the file you attach, it 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 text/plain. If the file contains binary information, then Mutt will mark it as application/octet-stream. You can change the MIME type that Mutt assigns to an attachment by using the <edit-type> command from the compose menu (default: ^T). The MIME type is actually a major mime type followed by the sub-type, separated by a '/'. 6 major types: application, text, image, video, audio, and model have been approved after various internet discussions. Mutt recognizes all of these if the appropriate entry is found in the mime.types file. It also recognizes other major mime types, such as the chemical type that is widely used in the molecular modeling community to pass molecular data in various forms to various molecular viewers. Non-recognized mime types should only be used if the recipient of the message is likely to be expecting such attachments.

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 mailcap 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.

In order to handle various MIME types that Mutt can not handle internally, Mutt 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:

where $HOME is your home directory. The $PKGDATADIR and the $SYSCONFDIR directories depend on where Mutt is installed: the former is the default for shared data, the latter for system configuration files.

The default search path can be obtained by running the following command:

mutt -nF /dev/null -Q mailcap_path

In particular, the metamail distribution will install a mailcap file, usually as /usr/local/etc/mailcap, which contains some baseline entries.

text/plain; more

text/plain; more %s

text/html; lynx %s

text/html; lynx -dump %s | more

text/html; lynx %s
text/*; more

text/test-mailcap-bug; cat %s; copiousoutput; test=charset=%{charset} \
        && test "`echo $charset | tr '[A-Z]' '[a-z]'`" != iso-8859-1

image/*;        xv %s
image/gif;      ; print= anytopnm %s | pnmtops | lpr; \
                nametemplate=%s.gif

text/html;      firefox -remote 'openURL(%s)' ; test=RunningX
text/html;      lynx %s; nametemplate=%s.html
text/html;      lynx -dump %s; nametemplate=%s.html; copiousoutput

# I'm always running X :)
video/*;        xanim %s > /dev/null
image/*;        xv %s > /dev/null

# I'm always running firefox (if my computer had more memory, maybe)
text/html;      firefox -remote 'openURL(%s)'

# Use xanim to view all videos   Xanim produces a header on startup,
# send that to /dev/null so I don't see it
video/*;        xanim %s > /dev/null

# Send html to a running firefox by remote
text/html;      firefox -remote 'openURL(%s)'; test=RunningFirefox

# If I'm not running firefox but I am running X, start firefox on the
# object
text/html;      firefox %s; test=RunningX

# Else use lynx to view it as text
text/html;      lynx %s

# This version would convert the text/html to text/plain
text/html;      lynx -dump %s; copiousoutput

# I use enscript to print text in two columns to a page
text/*;         more %s; print=enscript -2Gr %s

# Firefox adds a flag to tell itself to view jpegs internally
image/jpeg;xv %s; x-mozilla-flags=internal

# Use xv to view images if I'm running X
# In addition, this uses the \ to extend the line and set my editor
# for images
image/*;xv %s; test=RunningX; \
        edit=xpaint %s

# Convert images to text using the netpbm tools
image/*;  (anytopnm %s | pnmscale -xysize 80 46 | ppmtopgm | pgmtopbm |
pbmtoascii -1x2 ) 2>&1 ; copiousoutput

# Send excel spreadsheets to my NT box
application/ms-excel; open.pl %s

Usage:

In addition to explicitly telling Mutt to view an attachment with the MIME viewer defined in the mailcap file, Mutt has support for automatically viewing MIME attachments while in the pager.

To work, you must define a viewer in the mailcap file which uses the copiousoutput 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.

You then use the auto_view .muttrc command to list the content-types that you wish to view automatically. For instance, if you set it to:

auto_view text/html application/x-gunzip \
  application/postscript image/gif application/x-tar-gz

Mutt could use the following mailcap entries to automatically view attachments of these types.

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

unauto_view can be used to remove previous entries from the autoview list. This can be used with message-hook to autoview messages based on size, etc. “unauto_view *” will remove all previous entries.

Mutt has some heuristics for determining which attachment of a multipart/alternative type to display. First, Mutt will check the alternative_order list to determine if one of the available types is preferred. It consists of a number of mimetypes in order, including support for implicit and explicit wildcards, for example:

alternative_order text/enriched text/plain text application/postscript image/*

Next, Mutt will check if any of the types have a defined auto_view, and use that. Failing that, Mutt will look for any text type. As a last attempt, Mutt will look for any type it knows how to handle.

To remove a MIME type from the alternative_order list, use the unalternative_order command.

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 attachments and unattachments commands.

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.

The syntax is:

disposition is the attachment's Content-Disposition type — either inline or attachment. You can abbreviate this to I or A.

Disposition is prefixed by either a + symbol or a - symbol. If it's a +, you're saying that you want to allow this disposition and MIME type to qualify. If it's a -, you're saying that this disposition and MIME type is an exception to previous + rules. There are examples below of how this is useful.

mime-type is, unsurprisingly, the MIME type of the attachment you want to affect. A MIME type is always of the format major/minor, where major describes the broad category of document you're looking at, and minor describes the specific type within that category. The major part of mime-type must be literal text (or the special token “*”), but the minor part may be a regular expression. (Therefore, “*/.*” matches any MIME type.)

The MIME types you give to the attachments directive are a kind of pattern. When you use the attachments directive, the patterns you specify are added to a list. When you use unattachments, the pattern is removed from the list. The patterns are not expanded and matched to specific MIME types at this time — they're just text in a list. They're only matched when actually evaluating a message.

Some examples might help to illustrate. The examples that are not commented out define the default configuration of the lists.

## 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.
##
attachments   +A */.*
attachments   -A text/x-vcard application/pgp.*
attachments   -A application/x-pkcs7-.*

## 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?)
##
attachments   +I text/plain

## 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/.*

## You probably don't really care to know about deleted attachments.
attachments   -A message/external-body
attachments   -I message/external-body

Entering the command “attachments ?” as a command will list your current settings in Muttrc format, so that it can be pasted elsewhere.

Usage:

Mutt's mime_lookup list specifies a list of mime-types that should not be treated according to their mailcap entry. This option is designed to deal with binary types such as application/octet-stream. When an attachment's mime-type is listed in mime_lookup, then the extension of the filename will be compared to the to autoview messages based on size, etc. “unauto_view *” will remove all previous entries.

Mutt has some heuristics for determining which attachment of a multipart/alternative type to display. First, Mutt will check the alternative_order list to determine if one of the available types is preferred. It consists of a number of mimetypes in order, including support for implicit and explicit wildcards, for example:

alternative_order text/enriched text/plain text application/postscript image/*

Next, Mutt will check if any of the types have a defined auto_view, and use that. Failing that, Mutt will look for any text type. As a last attempt, Mutt will look for any type it knows how to handle.

To remove a MIME type from the alternative_order list, use the unalternative_order command.

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 attachments and unattachments commands.

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.

The syntax is:

disposition is the attachment's Content-Disposition type — either inline or attachment. You can abbreviate this to I or A.

Disposition is prefixed by either a + symbol or a - symbol. If it's a +, you're saying that you want to allow this disposition and MIME type to qualify. If it's a -, you're saying that this disposition and MIME type is an exception to previous + rules. There are examples below of how this is useful.

mime-type is, unsurprisingly, the MIME type of the attachment you want to affect. A MIME type is always of the format major/minor, where major describes the broad category of document you're looking at, and minor describes the specific type within that category. The major part of mime-type must be literal text (or the special token “*”), but the minor part may be a regular expression. (Therefore, “*/.*” matches any MIME type.)

The MIME types you give to the attachments directive are a kind of pattern. When you use the attachments directive, the patterns you specify are added to a list. When you use unattachments, the pattern is removed from the list. The patterns are not expanded and matched to specific MIME types at this time — they're just text in a list. They're only matched when actually evaluating a message.

Some examples might help to illustrate. The examples that are not commented out define the default configuration of the lists.

## 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.
##
attachments   +A */.*
attachments   -A text/x-vcard application/pgp.*
attachments   -A application/x-pkcs7-.*

## 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?)
##
attachments   +I text/plain

## 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/.*

## You probably don't really care to know about deleted attachments.
attachments   -A message/external-body
attachments   -I message/external-body

Entering the command “attachments ?” as a command will list your current settings in Muttrc format, so that it can be pasted elsewhere.

Usage:

Mutt's mime_lookup list specifies a list of mime-types that should not be treated according to their mailcap entry. This option is designed to deal with binary types such as application/octet-stream. When an attachment's mime-type is listed in mime_lookup, then the extension of the filename will be compared to the to autoview messages based on size, etc. “unauto_view *” will remove all previous entries.

Mutt has some heuristics for determining which attachment of a multipart/alternative type to display. First, Mutt will check the alternative_order list to determine if one of the available types is preferred. It consists of a number of mimetypes in order, including support for implicit and explicit wildcards, for example: