Table of Contents
+
Table of Contents
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
-mime.types file, which contains the mapping of file extensions to
+mime.types file, which contains the mapping of file extensions to
IANA MIME types. The other is the mailcap file, which specifies
the external commands to use for handling specific MIME types.
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. -
+
When you select a message from the index and view it in the pager, Mutt
decodes the message to a text representation. Mutt internally supports
a number of MIME types, including text/plain, text/enriched,
@@ -23,36 +44,32 @@ including PGP/MIME and application/pgp.
Mutt will denote attachments with a couple lines describing them. These lines are of the form: -
[-- Attachment #1: Description --] [-- Type: text/plain, Encoding: 7bit, Size: 10000 --]
-
Where the Description is the description or filename given for the
attachment, and the Encoding is one of
7bit/8bit/quoted-printable/base64/binary.
If Mutt cannot deal with a MIME type, it will display a message like: -
[-- image/gif is unsupported (use 'v' to view this part) --] -
- -
The default binding for view-attachments is `v', 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 ``tag-prefix'' operator. You can also reply to the
+and by using the âtag-prefixâ 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.
-Finally, you can apply the usual message-related functions (like
-resend-message, and the reply
-and forward functions) to attachments of type message/rfc822.
+Finally, you can apply the usual message-related functions (like
+<resend-message>, and the
+<reply> and <forward>
+functions) to attachments of type message/rfc822.
See the help on the attachment menu for more information.
@@ -65,13 +82,10 @@ list of tagged attachments. You can also modifying the attachment information, notably the type, encoding and description.
Attachments appear as follows: -
- 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>
- -
The '-' denotes that Mutt will delete the file after sending (or
postponing, or canceling) the message. It can be toggled with the
toggle-unlink command (default: u). The next field is the MIME
@@ -92,13 +106,11 @@ the system mime.types file at /usr/local/share/mutt/mime.t
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.
@@ -111,13 +123,13 @@ type that Mutt assigns to an attachment by using the edit-
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
+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
+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 @@ -129,9 +141,7 @@ 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: -
$HOME/.mailcap
$PKGDATADIR/mailcap
$SYSCONFDIR/mailcap
/etc/mailcap
/usr/etc/mailcap
/usr/local/etc/mailcap
-
where $HOME is your home directory. The
$PKGDATADIR and the
$SYSCONFDIR directories depend on where mutt
@@ -146,7 +156,7 @@ 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.
-
+
A mailcap file consists of a series of lines which are comments, blank, or definitions.
@@ -179,54 +189,44 @@ will remove the temporary file if it exists.
So, in the simplest form, you can send a text/plain message to the external pager more on stdin: -
text/plain; more
- Or, you could send the message as a file: -
text/plain; more %s
- -Perhaps you would like to use lynx to interactively view a text/html +Perhaps you would like to use lynx to interactively view a text/html message: -
text/html; lynx %s
- In this case, lynx does not support viewing a file from stdin, so you must use the %s syntax. -Note: Some older versions of lynx contain a bug where they +
+Some older versions of lynx contain a bug where they will check the mailcap file for a viewer for text/html. They will find the line which calls lynx, and run it. This causes lynx to continuously spawn itself to view the object. -
+
On the other hand, maybe you don't want to use lynx interactively, you just want to have it convert the text/html to text/plain, then you can use: -
text/html; lynx -dump %s | more
- -
Perhaps you wish to use lynx to view text/html files, and a pager on all other text formats, then you would use the following: -
text/html; lynx %s text/*; more
- This is the simplest form of a mailcap file. -
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 %s syntaxes properly, and avoids risky characters by -substituting them, see the $mailcap_sanitize variable. +substituting them, see the $mailcap_sanitize variable.
Although mutt's procedures to invoke programs with mailcap seem to be
safe, there are other applications parsing mailcap, maybe taking less care
@@ -245,14 +245,10 @@ quoting or backtick expansions, put that value into a shell variable
and reference the shell variable where necessary, as in the following
example (using $charset inside the backtick expansion is safe,
since it is not itself subject to any further expansion):
-
-
text/test-mailcap-bug; cat %s; copiousoutput; test=charset=%{charset} \
&& test "`echo $charset | tr '[A-Z]' '[a-z]'`" != iso-8859-1
-- -
In addition to the required content-type and view command fields, you
can add semi-colon ';' separated fields to set flags and other options.
Mutt recognizes the following optional fields:
@@ -263,19 +259,17 @@ 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 more
in the lynx -dump example in the Basic section:
-
text/html; lynx -dump %s ; copiousoutput
- This will cause lynx to format the text/html output as text/plain and Mutt will use your standard pager to display the results.
-Mutt uses this flag when viewing attachments with auto_view, in order to decide whether it should honor the setting
-of the $wait_key variable or
+Mutt uses this flag when viewing attachments with auto_view, in order to decide whether it should honor the setting
+of the $wait_key variable or
not. When an attachment is viewed using an interactive program, and the
corresponding mailcap entry has a needsterminal flag, Mutt will use
-$wait_key and the exit status
+$wait_key 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.
@@ -303,65 +297,55 @@ for instance, to correctly view a file. For instance, lynx will only
interpret a file as text/html if the file ends in .html.
So, you would specify lynx as a text/html viewer with a line in
the mailcap file like:
-
text/html; lynx %s; nametemplate=%s.html -
- -
+
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: the content-type must match before Mutt performs the test. +Note that the content-type must match before Mutt performs the test. For example: -
text/html; netscape -remote 'openURL(%s)' ; test=RunningX text/html; lynx %s
- In this example, Mutt will run the program RunningX which will return 0 if the X Window manager is running, and non-zero if it isn't. If RunningX returns 0, then Mutt will call netscape to display the text/html object. If RunningX doesn't return 0, then Mutt will go on to the next entry and use lynx to display the text/html object. -
-
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 image/gif, and you have the following
entries in your mailcap file, Mutt will search for an entry with the
print command:
-
image/*; xv %s
image/gif; ; print= anytopnm %s | pnmtops | lpr; \
nametemplate=%s.gif
-
Mutt will skip the image/* entry and use the image/gif
entry with the print command.
-In addition, you can use this with auto_view +In addition, you can use this with auto_view to denote two commands for viewing an attachment, one to be viewed automatically, the other to be viewed interactively from the attachment menu. In addition, you can then use the test feature to determine which viewer to use interactively depending on your environment. -
text/html; netscape -remote 'openURL(%s)' ; test=RunningX text/html; lynx %s; nametemplate=%s.html text/html; lynx -dump %s; nametemplate=%s.html; copiousoutput
- -For auto_view, Mutt will choose the third +For auto_view, Mutt will choose the third entry because of the copiousoutput tag. For interactive viewing, Mutt will run the program RunningX 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 various commands defined in the mailcap files are passed to the
/bin/sh shell using the system() function. Before the
command is passed to /bin/sh -c, it is parsed to expand
@@ -383,11 +367,9 @@ mailcap definition line, ie text/html or
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:
-
Content-Type: text/plain; charset=iso-8859-1
- then Mutt will expand %{charset} to iso-8859-1. The default metamail mailcap file uses this feature to test the charset to spawn an xterm using the right charset to view the message. @@ -397,10 +379,9 @@ This will be replaced by a % Mutt does not currently support the %F and %n keywords specified in RFC 1524. The main purpose of these parameters is for multipart messages, which is handled internally by Mutt. -
This mailcap file is fairly simple and standard: - -
+# I'm always running X :) video/*; xanim %s > /dev/null image/*; xv %s > /dev/null @@ -408,12 +389,8 @@ image/*; xv %s > /dev/null # I'm always running netscape (if my computer had more memory, maybe) text/html; netscape -remote 'openURL(%s)'- -
This mailcap file shows quite a number of examples: -
- -
+# 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 @@ -449,14 +426,12 @@ pbmtoascii -1x2 ) 2>&1 ; copiousoutput # Send excel spreadsheets to my NT box application/ms-excel; open.pl %s -- -
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
+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.
@@ -465,16 +440,12 @@ You then use the auto_view muttrc command to list t
content-types that you wish to view automatically.
For instance, if you set auto_view 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 | \ @@ -483,26 +454,21 @@ 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. +âunauto_viewâ 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. +âunauto_view *â 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 +multipart/alternative type to display. First, mutt will check the alternative_order list to determine if one of the available types is preferred. The alternative_order list 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 +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.
@@ -529,20 +495,21 @@ unattachments {+|-}disposition mime-type attachments ?
Disposition is the attachment's Content-disposition type -- either
-"inline" or "attachment". You can abbreviate this to I or A.
+inline or attachment.
+You can abbreviate this to I or A.
-Disposition is prefixed by either a + symbolor a - symbol. If it's +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 mim-type must be literal text (or the special token "*"), but
-the minor part may be a regular expression. (Therefore, "*/.*" matches
+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 â*â), but
+the minor part may be a regular expression. (Therefore, â*/.*â matches
any MIME type.)
The MIME types you give to the attachments directive are a kind of @@ -554,7 +521,7 @@ 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. -
+Example 5.1. Attachment counting
## Removing a pattern from a list removes that pattern literally. It ## does not remove any type matching the pattern. ## @@ -601,9 +568,10 @@ attachments +I text/plain ## You probably don't really care to know about deleted attachments. attachments -A message/external-body attachments -I message/external-body --"attachments ?" will list your current settings in Muttrc format, so -that it can be pasted elsewhere. +
+Entering the command â
attachments ?â +as a command will list your current settings in Muttrc format, so that +it can be pasted elsewhere.
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 @@ -613,12 +581,9 @@ be compared to the list of extensions in the mime.types 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 auto_view) specified. Common usage would be: -
mime_lookup application/octet-stream application/X-Lotus-Manuscript
- -
In addition, the unmime_lookup command may be used to disable this feature for any particular mime-type if it had been set, for example, in a global muttrc.