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30 </style></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 5. Mutt's MIME Support</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="advancedusage.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="optionalfeatures.html">Next</a></td></tr></table><hr /></div><div class="chapter" title="Chapter 5. Mutt's MIME Support"><div class="titlepage"><div><div><h2 class="title"><a id="mimesupport"></a>Chapter 5. Mutt's MIME Support</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="mimesupport.html#using-mime">1. Using MIME in Mutt</a></span></dt><dd><dl><dt><span class="sect2"><a href="mimesupport.html#mime-overview">1.1. MIME Overview</a></span></dt><dt><span class="sect2"><a href="mimesupport.html#mime-pager">1.2. Viewing MIME Messages in the Pager</a></span></dt><dt><span class="sect2"><a href="mimesupport.html#attach-menu">1.3. The Attachment Menu</a></span></dt><dt><span class="sect2"><a href="mimesupport.html#compose-menu">1.4. The Compose Menu</a></span></dt></dl></dd><dt><span class="sect1"><a href="mimesupport.html#mime-types">2. MIME Type Configuration with <code class="literal">mime.types</code></a></span></dt><dt><span class="sect1"><a href="mimesupport.html#mailcap">3. MIME Viewer Configuration with Mailcap</a></span></dt><dd><dl><dt><span class="sect2"><a href="mimesupport.html#mailcap-basics">3.1. The Basics of the Mailcap File</a></span></dt><dt><span class="sect2"><a href="mimesupport.html#secure-mailcap">3.2. Secure Use of Mailcap</a></span></dt><dt><span class="sect2"><a href="mimesupport.html#advanced-mailcap">3.3. Advanced Mailcap Usage</a></span></dt><dt><span class="sect2"><a href="mimesupport.html#mailcap-example">3.4. Example Mailcap Files</a></span></dt></dl></dd><dt><span class="sect1"><a href="mimesupport.html#auto-view">4. MIME Autoview</a></span></dt><dt><span class="sect1"><a href="mimesupport.html#alternative-order">5. MIME Multipart/Alternative</a></span></dt><dt><span class="sect1"><a href="mimesupport.html#attachments">6. Attachment Searching and Counting</a></span></dt><dt><span class="sect1"><a href="mimesupport.html#mime-lookup">7. MIME Lookup</a></span></dt></dl></div><p>
31 Quite a bit of effort has been made to make Mutt the premier text-mode
32 MIME MUA. Every effort has been made to provide the functionality that
33 the discerning MIME user requires, and the conformance to the standards
34 wherever possible. When configuring Mutt for MIME, there are two extra
35 types of configuration files which Mutt uses. One is the
36 <code class="literal">mime.types</code> file, which contains the mapping of file
37 extensions to IANA MIME types. The other is the
38 <code class="literal">mailcap</code> file, which specifies the external commands
39 to use for handling specific MIME types.
40 </p><div class="sect1" title="1. Using MIME in Mutt"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="using-mime"></a>1. Using MIME in Mutt</h2></div></div></div><div class="sect2" title="1.1. MIME Overview"><div class="titlepage"><div><div><h3 class="title"><a id="mime-overview"></a>1.1. MIME Overview</h3></div></div></div><p>
41 MIME is short for <span class="quote">“<span class="quote">Multipurpose Internet Mail Extension</span>”</span>
42 and describes mechanisms to internationalize and structure mail
43 messages. Before the introduction of MIME, messages had a single text
44 part and were limited to us-ascii header and content. With MIME,
45 messages can have attachments (and even attachments which itself have
46 attachments and thus form a tree structure), nearly arbitrary characters
47 can be used for sender names, recipients and subjects.
49 Besides the handling of non-ascii characters in message headers, to Mutt
50 the most important aspect of MIME are so-called MIME types. These are
51 constructed using a <span class="emphasis"><em>major</em></span> and
52 <span class="emphasis"><em>minor</em></span> type separated by a forward slash. These
53 specify details about the content that follows. Based upon these, Mutt
54 decides how to handle this part. The most popular major type is
55 <span class="quote">“<span class="quote"><code class="literal">text</code></span>”</span> with minor types for plain text,
56 HTML and various other formats. Major types also exist for images,
57 audio, video and of course general application data (e.g. to separate
58 cryptographically signed data with a signature, send office documents,
59 and in general arbitrary binary data). There's also the
60 <code class="literal">multipart</code> major type which represents the root of a
61 subtree of MIME parts. A list of supported MIME types can be found in
62 <a class="xref" href="mimesupport.html#supported-mime-types" title="Table 5.1. Supported MIME types">Table 5.1, “Supported MIME types”</a>.
64 MIME also defines a set of encoding schemes for transporting MIME
65 content over the network: <code class="literal">7bit</code>,
66 <code class="literal">8bit</code>, <code class="literal">quoted-printable</code>,
67 <code class="literal">base64</code> and <code class="literal">binary</code>. There're some
68 rules when to choose what for encoding headers and/or body (if needed),
69 and Mutt will in general make a good choice.
71 Mutt does most of MIME encoding/decoding behind the scenes to form
72 messages conforming to MIME on the sending side. On reception, it can be
73 flexibly configured as to how what MIME structure is displayed (and if
74 it's displayed): these decisions are based on the content's MIME type.
75 There are three areas/menus in dealing with MIME: the pager (while
76 viewing a message), the attachment menu and the compose menu.
77 </p></div><div class="sect2" title="1.2. Viewing MIME Messages in the Pager"><div class="titlepage"><div><div><h3 class="title"><a id="mime-pager"></a>1.2. Viewing MIME Messages in the Pager</h3></div></div></div><p>
78 When you select a message from the index and view it in the pager, Mutt
79 decodes as much of a message as possible to a text representation. Mutt
80 internally supports a number of MIME types, including the
81 <code class="literal">text</code> major type (with all minor types), the
82 <code class="literal">message/rfc822</code> (mail messages) type and some
83 <code class="literal">multipart</code> types. In addition, it recognizes a variety
84 of PGP MIME types, including PGP/MIME and
85 <code class="literal">application/pgp</code>.
87 Mutt will denote attachments with a couple lines describing them.
88 These lines are of the form:
89 </p><pre class="screen">
90 [-- Attachment #1: Description --]
91 [-- Type: text/plain, Encoding: 7bit, Size: 10000 --]
93 Where the <span class="emphasis"><em>Description</em></span> is the description or
94 filename given for the attachment, and the <span class="emphasis"><em>Encoding</em></span>
95 is one of the already mentioned content encodings.
97 If Mutt cannot deal with a MIME type, it will display a message like:
98 </p><pre class="screen">
99 [-- image/gif is unsupported (use 'v' to view this part) --]
100 </pre></div><div class="sect2" title="1.3. The Attachment Menu"><div class="titlepage"><div><div><h3 class="title"><a id="attach-menu"></a>1.3. The Attachment Menu</h3></div></div></div><p>
101 The default binding for <code class="literal"><view-attachments></code> is
102 <span class="quote">“<span class="quote">v</span>”</span>, which displays the attachment menu for a message. The
103 attachment menu displays a list of the attachments in a message. From
104 the attachment menu, you can save, print, pipe, delete, and view
105 attachments. You can apply these operations to a group of attachments
106 at once, by tagging the attachments and by using the
107 <code class="literal"><tag-prefix></code> operator. You can also reply to
108 the current message from this menu, and only the current attachment (or
109 the attachments tagged) will be quoted in your reply. You can view
110 attachments as text, or view them using the mailcap viewer definition
111 (the mailcap mechanism is explained later in detail).
113 Finally, you can apply the usual message-related functions (like <a class="link" href="gettingstarted.html#resend-message"><code class="literal"><resend-message></code></a>,
114 and the <code class="literal"><reply></code> and
115 <code class="literal"><forward></code> functions) to attachments of type
116 <code class="literal">message/rfc822</code>.
118 See table <a class="xref" href="reference.html#tab-attachment-bindings" title="Table 9.7. Default Attachment Menu Bindings">Table 9.7, “Default Attachment Menu Bindings”</a> for all available
120 </p></div><div class="sect2" title="1.4. The Compose Menu"><div class="titlepage"><div><div><h3 class="title"><a id="compose-menu"></a>1.4. The Compose Menu</h3></div></div></div><p>
121 The compose menu is the menu you see before you send a message. It
122 allows you to edit the recipient list, the subject, and other aspects of
123 your message. It also contains a list of the attachments of your
124 message, including the main body. From this menu, you can print, copy,
125 filter, pipe, edit, compose, review, and rename an attachment or a list
126 of tagged attachments. You can also modifying the attachment
127 information, notably the type, encoding and description.
129 Attachments appear as follows by default:
130 </p><pre class="screen">
131 - 1 [text/plain, 7bit, 1K] /tmp/mutt-euler-8082-0 <no description>
132 2 [applica/x-gunzip, base64, 422K] ~/src/mutt-0.85.tar.gz <no description>
134 The <span class="quote">“<span class="quote">-</span>”</span> denotes that Mutt will delete the file after
135 sending (or postponing, or canceling) the message. It can be toggled
136 with the <code class="literal"><toggle-unlink></code> command (default: u).
137 The next field is the MIME content-type, and can be changed with the
138 <code class="literal"><edit-type></code> command (default: ^T). The next
139 field is the encoding for the attachment, which allows a binary message
140 to be encoded for transmission on 7bit links. It can be changed with
141 the <code class="literal"><edit-encoding></code> command (default: ^E). The
142 next field is the size of the attachment, rounded to kilobytes or
143 megabytes. The next field is the filename, which can be changed with
144 the <code class="literal"><rename-file></code> command (default: R). The
145 final field is the description of the attachment, and can be changed
146 with the <code class="literal"><edit-description></code> command (default:
147 d). See <a class="link" href="reference.html#attach-format" title="3.13. attach_format">$attach_format</a> for a full
148 list of available expandos to format this display to your needs.
149 </p></div></div><div class="sect1" title="2. MIME Type Configuration with mime.types"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="mime-types"></a>2. MIME Type Configuration with <code class="literal">mime.types</code></h2></div></div></div><p>
150 To get most out of MIME, it's important that a MIME part's content type
151 matches the content as closely as possible so that the recipient's
152 client can automatically select the right viewer for the
153 content. However, there's no reliable for Mutt to know how to detect
154 every possible file type. Instead, it uses a simple plain text mapping
155 file that specifies what file extension corresponds to what MIME
156 type. This file is called <code class="literal">mime.types</code>.
158 When you add an attachment to your mail message, Mutt searches your
159 personal <code class="literal">mime.types</code> file at
160 <code class="literal">$HOME/.mime.types</code>, and then the system
161 <code class="literal">mime.types</code> file at
162 <code class="literal">/usr/local/share/mutt/mime.types</code> or
163 <code class="literal">/etc/mime.types</code>
165 Each line starts with the full MIME type, followed by a space and
166 space-separated list of file extensions. For example you could use:
167 </p><div class="example"><a id="ex-mime-types"></a><p class="title"><b>Example 5.1. <code class="literal">mime.types</code></b></p><div class="example-contents"><pre class="screen">
168 application/postscript ps eps
170 audio/x-aiff aif aifc aiff
171 </pre></div></div><br class="example-break" /><p>
172 A sample <code class="literal">mime.types</code> file comes with the Mutt
173 distribution, and should contain most of the MIME types you are likely
176 If Mutt can not determine the MIME type by the extension of the file you
177 attach, it will look at the file. If the file is free of binary
178 information, Mutt will assume that the file is plain text, and mark it
179 as <code class="literal">text/plain</code>. If the file contains binary
180 information, then Mutt will mark it as
181 <code class="literal">application/octet-stream</code>. You can change the MIME
182 type that Mutt assigns to an attachment by using the
183 <code class="literal"><edit-type></code> command from the compose menu
184 (default: ^T), see <a class="xref" href="mimesupport.html#supported-mime-types" title="Table 5.1. Supported MIME types">Table 5.1, “Supported MIME types”</a> for supported
185 major types. Mutt recognizes all of these if the appropriate entry is
186 found in the <code class="literal">mime.types</code> file. Non-recognized mime
187 types should only be used if the recipient of the message is likely to
188 be expecting such attachments.
189 </p><div class="table"><a id="supported-mime-types"></a><p class="title"><b>Table 5.1. Supported MIME types</b></p><div class="table-contents"><table summary="Supported MIME types" border="1"><colgroup><col /><col /><col /></colgroup><thead><tr><th>MIME major type</th><th>Standard</th><th>Description</th></tr></thead><tbody><tr><td><code class="literal">application</code></td><td>yes</td><td>General application data</td></tr><tr><td><code class="literal">audio</code></td><td>yes</td><td>Audio data</td></tr><tr><td><code class="literal">image</code></td><td>yes</td><td>Image data</td></tr><tr><td><code class="literal">message</code></td><td>yes</td><td>Mail messages, message status information</td></tr><tr><td><code class="literal">model</code></td><td>yes</td><td>VRML and other modeling data</td></tr><tr><td><code class="literal">multipart</code></td><td>yes</td><td>Container for other MIME parts</td></tr><tr><td><code class="literal">text</code></td><td>yes</td><td>Text data</td></tr><tr><td><code class="literal">video</code></td><td>yes</td><td>Video data</td></tr><tr><td><code class="literal">chemical</code></td><td>no</td><td>Mostly molecular data</td></tr></tbody></table></div></div><br class="table-break" /><p>
190 MIME types are not arbitrary, they need to be assigned by <a class="ulink" href="http://www.iana.org/assignments/media-types/" target="_top">IANA</a>.
191 </p></div><div class="sect1" title="3. MIME Viewer Configuration with Mailcap"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="mailcap"></a>3. MIME Viewer Configuration with Mailcap</h2></div></div></div><p>
192 Mutt supports RFC 1524 MIME Configuration, in particular the Unix
193 specific format specified in Appendix A of RFC 1524. This file format
194 is commonly referred to as the <span class="quote">“<span class="quote">mailcap</span>”</span> format. Many MIME
195 compliant programs utilize the mailcap format, allowing you to specify
196 handling for all MIME types in one place for all programs. Programs
197 known to use this format include Firefox, lynx and metamail.
199 In order to handle various MIME types that Mutt doesn't have built-in
200 support for, it parses a series of external configuration files to find
201 an external handler. The default search string for these files is a
202 colon delimited list containing the following files:
203 </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p><code class="literal">$HOME/.mailcap</code></p></li><li class="listitem"><p><code class="literal">$PKGDATADIR/mailcap</code></p></li><li class="listitem"><p><code class="literal">$SYSCONFDIR/mailcap</code></p></li><li class="listitem"><p><code class="literal">/etc/mailcap</code></p></li><li class="listitem"><p><code class="literal">/usr/etc/mailcap</code></p></li><li class="listitem"><p><code class="literal">/usr/local/etc/mailcap</code></p></li></ol></div><p>
204 where <code class="literal">$HOME</code> is your home directory. The
205 <code class="literal">$PKGDATADIR</code> and the <code class="literal">$SYSCONFDIR</code>
206 directories depend on where Mutt is installed: the former is the default
207 for shared data, the latter for system configuration files.
209 The default search path can be obtained by running the following
211 </p><pre class="screen">
212 mutt -nF /dev/null -Q mailcap_path
214 In particular, the metamail distribution will install a mailcap file,
215 usually as <code class="literal">/usr/local/etc/mailcap</code>, which contains
216 some baseline entries.
217 </p><div class="sect2" title="3.1. The Basics of the Mailcap File"><div class="titlepage"><div><div><h3 class="title"><a id="mailcap-basics"></a>3.1. The Basics of the Mailcap File</h3></div></div></div><p>
218 A mailcap file consists of a series of lines which are comments, blank,
221 A comment line consists of a # character followed by anything you want.
223 A blank line is blank.
225 A definition line consists of a content type, a view command, and any
226 number of optional fields. Each field of a definition line is divided
227 by a semicolon <span class="quote">“<span class="quote">;</span>”</span> character.
229 The content type is specified in the MIME standard
230 <span class="quote">“<span class="quote">type/subtype</span>”</span> notation. For example,
231 <code class="literal">text/plain</code>, <code class="literal">text/html</code>,
232 <code class="literal">image/gif</code>, etc. In addition, the mailcap format
233 includes two formats for wildcards, one using the special
234 <span class="quote">“<span class="quote">*</span>”</span> subtype, the other is the implicit wild, where you only
235 include the major type. For example, <code class="literal">image/*</code>, or
236 <code class="literal">video</code> will match all image types and video types,
239 The view command is a Unix command for viewing the type specified. There
240 are two different types of commands supported. The default is to send
241 the body of the MIME message to the command on stdin. You can change
242 this behavior by using <code class="literal">%s</code> as a parameter to your view
243 command. This will cause Mutt to save the body of the MIME message to a
244 temporary file, and then call the view command with the
245 <code class="literal">%s</code> replaced by the name of the temporary file. In
246 both cases, Mutt will turn over the terminal to the view program until
247 the program quits, at which time Mutt will remove the temporary file if
248 it exists. This means that mailcap does <span class="emphasis"><em>not</em></span> work
249 out of the box with programs which detach themselves from the terminal
250 right after starting, like <code class="literal">open</code> on Mac OS X. In order
251 to nevertheless use these programs with mailcap, you probably need
252 custom shell scripts.
254 So, in the simplest form, you can send a <code class="literal">text/plain</code>
255 message to the external pager more on standard input:
256 </p><pre class="screen">
259 Or, you could send the message as a file:
260 </p><pre class="screen">
263 Perhaps you would like to use lynx to interactively view a
264 <code class="literal">text/html</code> message:
265 </p><pre class="screen">
268 In this case, lynx does not support viewing a file from standard input,
269 so you must use the <code class="literal">%s</code> syntax.
270 </p><div class="note" title="Note"><h3 class="title">Note</h3><p>
271 <span class="emphasis"><em>Some older versions of lynx contain a bug where they will
272 check the mailcap file for a viewer for <code class="literal">text/html</code>.
273 They will find the line which calls lynx, and run it. This causes lynx
274 to continuously spawn itself to view the object.</em></span>
276 On the other hand, maybe you don't want to use lynx interactively, you
277 just want to have it convert the <code class="literal">text/html</code> to
278 <code class="literal">text/plain</code>, then you can use:
279 </p><pre class="screen">
280 text/html; lynx -dump %s | more
282 Perhaps you wish to use lynx to view <code class="literal">text/html</code> files,
283 and a pager on all other text formats, then you would use the following:
284 </p><pre class="screen">
287 </pre></div><div class="sect2" title="3.2. Secure Use of Mailcap"><div class="titlepage"><div><div><h3 class="title"><a id="secure-mailcap"></a>3.2. Secure Use of Mailcap</h3></div></div></div><p>
288 The interpretation of shell meta-characters embedded in MIME parameters
289 can lead to security problems in general. Mutt tries to quote
290 parameters in expansion of <code class="literal">%s</code> syntaxes properly, and
291 avoids risky characters by substituting them, see the <a class="link" href="reference.html#mailcap-sanitize" title="3.121. mailcap_sanitize">$mailcap_sanitize</a> variable.
293 Although Mutt's procedures to invoke programs with mailcap seem to be
294 safe, there are other applications parsing mailcap, maybe taking less
295 care of it. Therefore you should pay attention to the following rules:
297 <span class="emphasis"><em>Keep the %-expandos away from shell quoting.</em></span> Don't
298 quote them with single or double quotes. Mutt does this for you, the
299 right way, as should any other program which interprets mailcap. Don't
300 put them into backtick expansions. Be highly careful with evil
301 statements, and avoid them if possible at all. Trying to fix broken
302 behavior with quotes introduces new leaks — there is no
303 alternative to correct quoting in the first place.
305 If you have to use the %-expandos' values in context where you need
306 quoting or backtick expansions, put that value into a shell variable and
307 reference the shell variable where necessary, as in the following
308 example (using <code class="literal">$charset</code> inside the backtick expansion
309 is safe, since it is not itself subject to any further expansion):
310 </p><pre class="screen">
311 text/test-mailcap-bug; cat %s; copiousoutput; test=charset=%{charset} \
312 && test "`echo $charset | tr '[A-Z]' '[a-z]'`" != iso-8859-1
313 </pre></div><div class="sect2" title="3.3. Advanced Mailcap Usage"><div class="titlepage"><div><div><h3 class="title"><a id="advanced-mailcap"></a>3.3. Advanced Mailcap Usage</h3></div></div></div><div class="sect3" title="3.3.1. Optional Fields"><div class="titlepage"><div><div><h4 class="title"><a id="optional-mailcap-fields"></a>3.3.1. Optional Fields</h4></div></div></div><p>
314 In addition to the required content-type and view command fields, you
315 can add semi-colon <span class="quote">“<span class="quote">;</span>”</span> separated fields to set flags and
316 other options. Mutt recognizes the following optional fields:
317 </p><div class="variablelist"><dl><dt><span class="term">copiousoutput</span></dt><dd><p>
318 This flag tells Mutt that the command passes possibly large amounts of
319 text on standard output. This causes Mutt to invoke a pager (either
320 the internal pager or the external pager defined by the pager variable)
321 on the output of the view command. Without this flag, Mutt assumes that
322 the command is interactive. One could use this to replace the pipe to
323 <code class="literal">more</code> in the <code class="literal">lynx -dump</code> example in
325 </p><pre class="screen">
326 text/html; lynx -dump %s ; copiousoutput
328 This will cause lynx to format the <code class="literal">text/html</code> output
329 as <code class="literal">text/plain</code> and Mutt will use your standard pager
330 to display the results.
332 Note that when using the built-in pager, <span class="emphasis"><em>only</em></span>
333 entries with this flag will be considered a handler for a MIME type
334 — all other entries will be ignored.
335 </p></dd><dt><span class="term">needsterminal</span></dt><dd><p>
336 Mutt uses this flag when viewing attachments with <a class="link" href="mimesupport.html#auto-view" title="4. MIME Autoview"><span class="command"><strong>auto_view</strong></span></a>, in order to
337 decide whether it should honor the setting of the <a class="link" href="reference.html#wait-key" title="3.305. wait_key">$wait_key</a> variable or not. When an attachment
338 is viewed using an interactive program, and the corresponding mailcap
339 entry has a <span class="emphasis"><em>needsterminal</em></span> flag, Mutt will use <a class="link" href="reference.html#wait-key" title="3.305. wait_key">$wait_key</a> and the exit status of the program
340 to decide if it will ask you to press a key after the external program
341 has exited. In all other situations it will not prompt you for a key.
342 </p></dd><dt><span class="term">compose=<command></span></dt><dd><p>
343 This flag specifies the command to use to create a new attachment of a
344 specific MIME type. Mutt supports this from the compose menu.
345 </p></dd><dt><span class="term">composetyped=<command></span></dt><dd><p>
346 This flag specifies the command to use to create a new attachment of a
347 specific MIME type. This command differs from the compose command in
348 that Mutt will expect standard MIME headers on the data. This can be
349 used to specify parameters, filename, description, etc. for a new
350 attachment. Mutt supports this from the compose menu.
351 </p></dd><dt><span class="term">print=<command></span></dt><dd><p>
352 This flag specifies the command to use to print a specific MIME type.
353 Mutt supports this from the attachment and compose menus.
354 </p></dd><dt><span class="term">edit=<command></span></dt><dd><p>
355 This flag specifies the command to use to edit a specific MIME type.
356 Mutt supports this from the compose menu, and also uses it to compose
357 new attachments. Mutt will default to the defined <a class="link" href="reference.html#editor" title="3.58. editor">$editor</a> for text attachments.
358 </p></dd><dt><span class="term">nametemplate=<template></span></dt><dd><p>
359 This field specifies the format for the file denoted by
360 <code class="literal">%s</code> in the command fields. Certain programs will
361 require a certain file extension, for instance, to correctly view a
362 file. For instance, lynx will only interpret a file as
363 <code class="literal">text/html</code> if the file ends in
364 <code class="literal">.html</code>. So, you would specify lynx as a
365 <code class="literal">text/html</code> viewer with a line in the mailcap file
367 </p><pre class="screen">
368 text/html; lynx %s; nametemplate=%s.html
369 </pre></dd><dt><span class="term">test=<command></span></dt><dd><p>
370 This field specifies a command to run to test whether this mailcap entry
371 should be used. The command is defined with the command expansion rules
372 defined in the next section. If the command returns 0, then the test
373 passed, and Mutt uses this entry. If the command returns non-zero, then
374 the test failed, and Mutt continues searching for the right entry. Note
375 that the content-type must match before Mutt performs the test. For
377 </p><pre class="screen">
378 text/html; firefox -remote 'openURL(%s)' ; test=RunningX
381 In this example, Mutt will run the program <code class="literal">RunningX</code>
382 which will return 0 if the X Window manager is running, and non-zero if
383 it isn't. If <code class="literal">RunningX</code> returns 0, then Mutt will run
384 firefox to display the <code class="literal">text/html</code> object. If RunningX
385 doesn't return 0, then Mutt will go on to the next entry and use lynx to
386 display the <code class="literal">text/html</code> object.
387 </p></dd></dl></div></div><div class="sect3" title="3.3.2. Search Order"><div class="titlepage"><div><div><h4 class="title"><a id="mailcap-search-order"></a>3.3.2. Search Order</h4></div></div></div><p>
388 When searching for an entry in the mailcap file, Mutt will search for
389 the most useful entry for its purpose. For instance, if you are
390 attempting to print an <code class="literal">image/gif</code>, and you have the
391 following entries in your mailcap file, Mutt will search for an entry
392 with the print command:
393 </p><pre class="screen">
395 image/gif; ; print= anytopnm %s | pnmtops | lpr; \
398 Mutt will skip the <code class="literal">image/*</code> entry and use the
399 <code class="literal">image/gif</code> entry with the print command.
401 In addition, you can use this with <a class="link" href="mimesupport.html#auto-view" title="4. MIME Autoview"><span class="command"><strong>auto_view</strong></span></a> to denote two
402 commands for viewing an attachment, one to be viewed automatically, the
403 other to be viewed interactively from the attachment menu using the
404 <code class="literal"><view-mailcap></code> function (bound to
405 <span class="quote">“<span class="quote">m</span>”</span> by default). In addition, you can then use the test
406 feature to determine which viewer to use interactively depending on your
408 </p><pre class="screen">
409 text/html; firefox -remote 'openURL(%s)' ; test=RunningX
410 text/html; lynx %s; nametemplate=%s.html
411 text/html; lynx -dump %s; nametemplate=%s.html; copiousoutput
413 For <a class="link" href="mimesupport.html#auto-view" title="4. MIME Autoview"><span class="command"><strong>auto_view</strong></span></a>, Mutt
414 will choose the third entry because of the
415 <code class="literal">copiousoutput</code> tag. For interactive viewing, Mutt
416 will run the program <code class="literal">RunningX</code> to determine if it
417 should use the first entry. If the program returns non-zero, Mutt will
418 use the second entry for interactive viewing. The last entry is for
419 inline display in the pager and the
420 <code class="literal"><view-attach></code> function in the attachment menu.
422 Entries with the <code class="literal">copiousoutput</code> tag should always be
423 specified as the last one per type. For non-interactive use, the last
424 entry will then actually be the first matching one with the tag set.
425 For non-interactive use, only <code class="literal">copiousoutput</code>-tagged
426 entries are considered. For interactive use, Mutt ignores this tag and
427 treats all entries equally. Therefore, if not specified last, all
428 following entries without this tag would never be considered for
429 <code class="literal"><view-attach></code> because the
430 <code class="literal">copiousoutput</code> before them matched already.
431 </p></div><div class="sect3" title="3.3.3. Command Expansion"><div class="titlepage"><div><div><h4 class="title"><a id="mailcap-command-expansion"></a>3.3.3. Command Expansion</h4></div></div></div><p>
432 The various commands defined in the mailcap files are passed to the
433 <code class="literal">/bin/sh</code> shell using the <code class="literal">system(3)</code>
434 function. Before the command is passed to <code class="literal">/bin/sh
435 -c</code>, it is parsed to expand various special parameters with
436 information from Mutt. The keywords Mutt expands are:
437 </p><div class="variablelist"><dl><dt><span class="term">%s</span></dt><dd><p>
438 As seen in the basic mailcap section, this variable is expanded to a
439 filename specified by the calling program. This file contains the body
440 of the message to view/print/edit or where the composing program should
441 place the results of composition. In addition, the use of this keyword
442 causes Mutt to not pass the body of the message to the view/print/edit
444 </p></dd><dt><span class="term">%t</span></dt><dd><p>
445 Mutt will expand <code class="literal">%t</code> to the text representation of the
446 content type of the message in the same form as the first parameter of
447 the mailcap definition line, i.e. <code class="literal">text/html</code> or
448 <code class="literal">image/gif</code>.
449 </p></dd><dt><span class="term">%{<parameter>}</span></dt><dd><p>
450 Mutt will expand this to the value of the specified parameter from the
451 Content-Type: line of the mail message. For instance, if your mail
453 </p><pre class="screen">
454 Content-Type: text/plain; charset=iso-8859-1
456 then Mutt will expand <code class="literal">%{charset}</code> to
457 <span class="quote">“<span class="quote">iso-8859-1</span>”</span>. The default metamail mailcap file uses this
458 feature to test the charset to spawn an xterm using the right charset to
460 </p></dd><dt><span class="term">\%</span></dt><dd><p>
461 This will be replaced by a literal <code class="literal">%</code>.
462 </p></dd></dl></div><p>
463 Mutt does not currently support the <code class="literal">%F</code> and
464 <code class="literal">%n</code> keywords specified in RFC 1524. The main purpose
465 of these parameters is for multipart messages, which is handled
467 </p></div></div><div class="sect2" title="3.4. Example Mailcap Files"><div class="titlepage"><div><div><h3 class="title"><a id="mailcap-example"></a>3.4. Example Mailcap Files</h3></div></div></div><p>
468 This mailcap file is fairly simple and standard:
469 </p><pre class="screen">
470 <span class="comment"># I'm always running X :)</span>
471 video/*; xanim %s > /dev/null
472 image/*; xv %s > /dev/null
474 <span class="comment"># I'm always running firefox (if my computer had more memory, maybe)</span>
475 text/html; firefox -remote 'openURL(%s)'
477 This mailcap file shows quite a number of examples:
478 </p><pre class="screen">
479 <span class="comment"># Use xanim to view all videos Xanim produces a header on startup,
480 # send that to /dev/null so I don't see it</span>
481 video/*; xanim %s > /dev/null
483 <span class="comment"># Send html to a running firefox by remote</span>
484 text/html; firefox -remote 'openURL(%s)'; test=RunningFirefox
486 <span class="comment"># If I'm not running firefox but I am running X, start firefox on the
488 text/html; firefox %s; test=RunningX
490 <span class="comment"># Else use lynx to view it as text</span>
493 <span class="comment"># This version would convert the text/html to text/plain</span>
494 text/html; lynx -dump %s; copiousoutput
496 <span class="comment"># I use enscript to print text in two columns to a page</span>
497 text/*; more %s; print=enscript -2Gr %s
499 <span class="comment"># Firefox adds a flag to tell itself to view jpegs internally</span>
500 image/jpeg;xv %s; x-mozilla-flags=internal
502 <span class="comment"># Use xv to view images if I'm running X</span>
503 <span class="comment"># In addition, this uses the \ to extend the line and set my editor</span>
504 <span class="comment"># for images</span>
505 image/*;xv %s; test=RunningX; \
508 <span class="comment"># Convert images to text using the netpbm tools</span>
509 image/*; (anytopnm %s | pnmscale -xysize 80 46 | ppmtopgm | pgmtopbm |
510 pbmtoascii -1x2 ) 2>&1 ; copiousoutput
512 <span class="comment"># Send excel spreadsheets to my NT box</span>
513 application/ms-excel; open.pl %s
514 </pre></div></div><div class="sect1" title="4. MIME Autoview"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="auto-view"></a>4. MIME Autoview</h2></div></div></div><p>
516 </p><div class="cmdsynopsis"><p><code class="command">auto_view</code>
517 <em class="replaceable"><code>mimetype</code></em>
519 <em class="replaceable"><code>mimetype</code></em>
520 ...]<br /><code class="command">unauto_view</code> {
521 <em class="replaceable"><code>*</code></em>
523 <em class="replaceable"><code>mimetype</code></em>
525 In addition to explicitly telling Mutt to view an attachment with the
526 MIME viewer defined in the mailcap file from the attachments menu, Mutt
527 has support for automatically viewing MIME attachments while in the
530 For this to work, you must define a viewer in the mailcap file which
531 uses the <code class="literal">copiousoutput</code> option to denote that it is
532 non-interactive. Usually, you also use the entry to convert the
533 attachment to a text representation which you can view in the pager.
535 You then use the <span class="command"><strong>auto_view</strong></span> configuration command to
536 list the content-types that you wish to view automatically. For
537 instance, if you set it to:
538 </p><pre class="screen">
539 auto_view text/html application/x-gunzip \
540 application/postscript image/gif application/x-tar-gz
542 ...Mutt would try to find corresponding entries for rendering
543 attachments of these types as text. A corresponding mailcap could look
545 </p><pre class="screen">
546 text/html; lynx -dump %s; copiousoutput; nametemplate=%s.html
547 image/*; anytopnm %s | pnmscale -xsize 80 -ysize 50 | ppmtopgm | \
548 pgmtopbm | pbmtoascii ; copiousoutput
549 application/x-gunzip; gzcat; copiousoutput
550 application/x-tar-gz; gunzip -c %s | tar -tf - ; copiousoutput
551 application/postscript; ps2ascii %s; copiousoutput
553 <span class="command"><strong>unauto_view</strong></span> can be used to remove previous entries
554 from the <span class="command"><strong>auto_view</strong></span> list. This can be used with <a class="link" href="configuration.html#message-hook" title="20. Change Settings Before Formatting a Message"><span class="command"><strong>message-hook</strong></span></a> to
555 autoview messages based on size, etc.
556 <span class="quote">“<span class="quote"><span class="command"><strong>unauto_view</strong></span> *</span>”</span> will remove all previous
558 </p></div><div class="sect1" title="5. MIME Multipart/Alternative"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="alternative-order"></a>5. MIME Multipart/Alternative</h2></div></div></div><p>
559 The <code class="literal">multipart/alternative</code> container type only has
560 child MIME parts which represent the same content in an alternative
561 way. This is often used to send HTML messages which contain an
562 alternative plain text representation.
564 Mutt has some heuristics for determining which attachment of a
565 <code class="literal">multipart/alternative</code> type to display:
566 </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>
567 First, Mutt will check the <span class="command"><strong>alternative_order</strong></span> list to
568 determine if one of the available types is preferred. It consists of a
569 number of MIME types in order, including support for implicit and
570 explicit wildcards. For example:
571 </p><pre class="screen">
572 alternative_order text/enriched text/plain text \
573 application/postscript image/*
574 </pre></li><li class="listitem"><p>
575 Next, Mutt will check if any of the types have a defined <a class="link" href="mimesupport.html#auto-view" title="4. MIME Autoview"><span class="command"><strong>auto_view</strong></span></a>, and use that.
576 </p></li><li class="listitem"><p>
577 Failing that, Mutt will look for any text type.
578 </p></li><li class="listitem"><p>
579 As a last attempt, Mutt will look for any type it knows how to handle.
580 </p></li></ol></div><p>
581 To remove a MIME type from the <span class="command"><strong>alternative_order</strong></span>
582 list, use the <span class="command"><strong>unalternative_order</strong></span> command.
583 </p></div><div class="sect1" title="6. Attachment Searching and Counting"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="attachments"></a>6. Attachment Searching and Counting</h2></div></div></div><p>
584 If you ever lose track of attachments in your mailboxes, Mutt's
585 attachment-counting and -searching support might be for you. You can
586 make your message index display the number of qualifying attachments in
587 each message, or search for messages by attachment count. You also can
588 configure what kinds of attachments qualify for this feature with the
589 <span class="command"><strong>attachments</strong></span> and <span class="command"><strong>unattachments</strong></span>
592 In order to provide this information, Mutt needs to fully MIME-parse all
593 messages affected first. This can slow down operation especially for
594 remote mail folders such as IMAP because all messages have to be
595 downloaded first regardless whether the user really wants to view them
596 or not though using <a class="xref" href="optionalfeatures.html#body-caching" title="7.2. Body Caching">Section 7.2, “Body Caching”</a> usually means to
597 download the message just once.
600 </p><div class="cmdsynopsis"><p><code class="command">attachments</code>
601 <em class="replaceable"><code>{ + | - }disposition</code></em>
603 <em class="replaceable"><code>mime-type</code></em>
604 <br /><code class="command">unattachments</code>
605 <em class="replaceable"><code>{ + | - }disposition</code></em>
607 <em class="replaceable"><code>mime-type</code></em>
608 <br /><code class="command">attachments</code>
609 <em class="replaceable"><code>?</code></em>
611 <span class="emphasis"><em>disposition</em></span> is the attachment's Content-Disposition
612 type — either <code class="literal">inline</code> or
613 <code class="literal">attachment</code>. You can abbreviate this to
614 <code class="literal">I</code> or <code class="literal">A</code>.
616 Disposition is prefixed by either a <span class="quote">“<span class="quote">+</span>”</span> symbol or a
617 <span class="quote">“<span class="quote">-</span>”</span> symbol. If it's a <span class="quote">“<span class="quote">+</span>”</span>, you're saying that
618 you want to allow this disposition and MIME type to qualify. If it's a
619 <span class="quote">“<span class="quote">-</span>”</span>, you're saying that this disposition and MIME type is
620 an exception to previous <span class="quote">“<span class="quote">+</span>”</span> rules. There are examples
621 below of how this is useful.
623 <span class="emphasis"><em>mime-type</em></span> is the MIME type of the attachment you
624 want the command to affect. A MIME type is always of the format
625 <code class="literal">major/minor</code>, where <code class="literal">major</code> describes
626 the broad category of document you're looking at, and
627 <code class="literal">minor</code> describes the specific type within that
628 category. The major part of mime-type must be literal text (or the
629 special token <span class="quote">“<span class="quote"><code class="literal">*</code></span>”</span>), but the minor part
630 may be a regular expression. (Therefore,
631 <span class="quote">“<span class="quote"><code class="literal">*/.*</code></span>”</span> matches any MIME type.)
633 The MIME types you give to the <span class="command"><strong>attachments</strong></span> directive
634 are a kind of pattern. When you use the <span class="command"><strong>attachments</strong></span>
635 directive, the patterns you specify are added to a list. When you use
636 <span class="command"><strong>unattachments</strong></span>, the pattern is removed from the list.
637 The patterns are not expanded and matched to specific MIME types at this
638 time — they're just text in a list. They're only matched when
639 actually evaluating a message.
641 Some examples might help to illustrate. The examples that are not
642 commented out define the default configuration of the lists.
643 </p><div class="example"><a id="ex-attach-count"></a><p class="title"><b>Example 5.2. Attachment counting</b></p><div class="example-contents"><pre class="screen">
644 <span class="comment">
645 # Removing a pattern from a list removes that pattern literally. It
646 # does not remove any type matching the pattern.
648 # attachments +A */.*
649 # attachments +A image/jpeg
650 # unattachments +A */.*
652 # This leaves "attached" image/jpeg files on the allowed attachments
653 # list. It does not remove all items, as you might expect, because the
654 # second */.* is not a matching expression at this time.
656 # Remember: "unattachments" only undoes what "attachments" has done!
657 # It does not trigger any matching on actual messages.
659 # Qualify any MIME part with an "attachment" disposition, EXCEPT for
660 # text/x-vcard and application/pgp parts. (PGP parts are already known
661 # to mutt, and can be searched for with ~g, ~G, and ~k.)
663 # I've added x-pkcs7 to this, since it functions (for S/MIME)
664 # analogously to PGP signature attachments. S/MIME isn't supported
665 # in a stock mutt build, but we can still treat it specially here.
669 attachments -A text/x-vcard application/pgp.*
670 attachments -A application/x-pkcs7-.*
672 <span class="comment">
673 # Discount all MIME parts with an "inline" disposition, unless they're
674 # text/plain. (Why inline a text/plain part unless it's external to the
677 attachments +I text/plain
679 <span class="comment">
680 # These two lines make Mutt qualify MIME containers. (So, for example,
681 # a message/rfc822 forward will count as an attachment.) The first
682 # line is unnecessary if you already have "attach-allow */.*", of
683 # course. These are off by default! The MIME elements contained
684 # within a message/* or multipart/* are still examined, even if the
685 # containers themselves don't qualify.
687 #attachments +A message/.* multipart/.*
688 #attachments +I message/.* multipart/.*
691 <span class="comment">## You probably don't really care to know about deleted attachments.</span>
692 attachments -A message/external-body
693 attachments -I message/external-body
694 </pre></div></div><br class="example-break" /><p>
695 Entering the command <span class="quote">“<span class="quote"><span class="command"><strong>attachments</strong></span> ?</span>”</span> as
696 a command will list your current settings in Muttrc format, so that it
697 can be pasted elsewhere.
698 </p></div><div class="sect1" title="7. MIME Lookup"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="mime-lookup"></a>7. MIME Lookup</h2></div></div></div><p>
700 </p><div class="cmdsynopsis"><p><code class="command">mime-lookup</code>
701 <em class="replaceable"><code>mimetype</code></em>
703 <em class="replaceable"><code>mimetype</code></em>
704 ...]<br /><code class="command">unmime-lookup</code> {
705 <em class="replaceable"><code>*</code></em>
707 <em class="replaceable"><code>mimetype</code></em>
709 Mutt's <span class="command"><strong>mime_lookup</strong></span> list specifies a list of MIME
710 types that should <span class="emphasis"><em>not</em></span> be treated according to their
711 mailcap entry. This option is designed to deal with binary types such
712 as <code class="literal">application/octet-stream</code>. When an attachment's
713 MIME type is listed in <span class="command"><strong>mime_lookup</strong></span>, then the
714 extension of the filename will be compared to the list of extensions in
715 the <code class="literal">mime.types</code> file. The MIME type associated with
716 this extension will then be used to process the attachment according to
717 the rules in the mailcap file and according to any other configuration
718 options (such as <span class="command"><strong>auto_view</strong></span>) specified. Common usage
720 </p><pre class="screen">
721 mime_lookup application/octet-stream application/X-Lotus-Manuscript
723 In addition, the <code class="literal">unmime_lookup</code> command may be used to
724 disable this feature for any particular MIME type if it had been set,
725 for example, in a global <code class="literal">.muttrc</code>.
726 </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="advancedusage.html">Prev</a> </td><td width="20%" align="center"> </td><td width="40%" align="right"> <a accesskey="n" href="optionalfeatures.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 4. Advanced Usage </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 6. Optional Features</td></tr></table></div></body></html>
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