4 .TH MHSHOW %manext1% "%nmhdate%" MH.6.8 [%nmhversion%]
6 mhshow \- display MIME messages
29 command display contents of a MIME (multi-media)
30 message or collection of messages.
33 manipulates multi-media messages as specified in
34 RFC\-2045 thru RFC\-2049. Currently
37 encodings in message bodies, and does not support the encoding of
38 message headers as specified in RFC\-2047.
42 will display all parts of a multipart
50 to particular subparts (of a
51 multipart content) and/or particular content types.
58 to use the specified file as
59 the source message, rather than a message from a folder. If you specify
60 this file as \*(lq-\*(rq, then
62 will accept the source message
63 on the standard input. Note that the file, or input from standard input
64 should be a validly formatted message, just like any other
68 be in mail drop format (to convert a file in
69 mail drop format to a folder of
74 When displaying multiple messages,
76 prepends each of them with a `>>> Message nnn' header,
77 and separates the messages with two lines of space.
78 This is similar to the way
80 acts on multiple files.
82 A part specification consists of a series of numbers separated by dots.
83 For example, in a multipart content containing three parts, these
84 would be named as 1, 2, and 3, respectively. If part 2 was also a
85 multipart content containing two parts, these would be named as 2.1 and
86 2.2, respectively. Note that the
88 switch is effective for only
89 messages containing a multipart content. If a message has some other
90 kind of content, or if the part is itself another multipart content, the
92 switch will not prevent the content from being acted upon.
94 A content specification consists of a content type and a subtype.
95 The initial list of \*(lqstandard\*(rq content types and subtypes can
96 be found in RFC\-2046.
98 A list of commonly used contents is briefly reproduced here:
102 .ta \w'application 'u
106 multipart mixed, alternative, digest, parallel
107 message rfc822, partial, external-body
108 application octet-stream, postscript
115 A legal MIME message must contain a subtype specification.
117 To specify a content, regardless of its subtype, just use the
118 name of the content, e.g., \*(lqaudio\*(rq. To specify a specific
119 subtype, separate the two with a slash, e.g., \*(lqaudio/basic\*(rq.
120 Note that regardless of the values given to the `\-type' switch, a
121 multipart content (of any subtype listed above) is always acted upon.
122 .SS "Unseen Sequence"
123 If the profile entry \*(lqUnseen\-Sequence\*(rq is present and
126 will remove each of the messages shown
127 from each sequence named by the profile entry.
128 .SS "Showing the Contents"
130 prints messages in a convenient representation.
133 is outputting to a terminal, then
134 a pager will be placed between the terminal and
137 The headers of each message are displayed with
139 using the standard format file
141 You may specify an alternate format file with the
144 switch. If the format file
146 is specified, then the display
147 of the message headers is suppressed.
149 Next, the contents are extracted from the message and are stored in
150 a temporary file. Usually, the name of the temporary file is the
151 word \*(lqmhshow\*(rq followed by a string of characters. Occasionally,
152 the method used to display a content (described next), requires that
153 the file end in a specific suffix. For example, the
155 command (part of the StarOffice package) can be used to display
156 Microsoft Word content, but it uses the suffix to determine how to display
157 the file. If no suffix is present, the file is not correctly loaded.
158 Similarily, older versions of the
160 command append a \*(lq.ps\*(rq suffix to
161 the filename if one was missing. As a result, these cannot be used to read
162 the default temporary file.
164 To get around this, your profile can contain lines of the forms:
168 mhshow-suffix-<type>/<subtype>: <suffix>
169 mhshow-suffix-<type>: <suffix>
173 to specify a suffix which can be automatically added to the temporary
174 file created for a specific content type. For example, the following
175 lines might appear in your profile:
179 mhshow-suffix-text: .txt
180 mhshow-suffix-application/msword: .doc
181 mhshow-suffix-application/PostScript: .ps
185 to automatically append a suffix to the temporary files.
187 The method used to display the different contents in the messages bodies
188 will be determined by a \*(lqdisplay string\*(rq. To find the display
191 will first search your profile for an entry of the form:
194 mhshow-show-<type>/<subtype>
197 to determine the display string. If this isn't found,
199 will search for an entry of the form:
205 to determine the display string.
207 If a display string is found, any escapes (given below) will be expanded.
208 The result will be executed under
209 \*(lq/bin/sh\*(rq, with the standard input
212 The display string may contain the following escapes:
217 %l Display listing prior to displaying content
218 %f Insert filename containing content
219 %F %f, but stdin is terminal not content
220 %a Insert parameters from Content-Type field
221 %s Insert content subtype
222 %c Insert foreign charset
223 %d Insert content description
229 processes the MIME parts serially, i.e. the next display process
230 is executed after the previous one has terminated.
234 is display a content, typing QUIT (usually
235 control-\\) will tell
237 to wrap things up immediately.
239 Note that if the content being displayed is multipart, but not one of
240 the subtypes listed above, then the f- and F-escapes expand to multiple
241 filenames, one for each subordinate content. Further, stdin is not
242 redirected from the terminal to the content.
244 If a display string is not found,
246 has the following default values:
250 mhshow-show-text/plain: %liconv -f <source-charset>
251 mhshow-show-message/rfc822: %lshow \-file %F
255 If a subtype of type text doesn't have a profile entry, it will be
256 treated as text/plain.
259 has default methods for handling multipart messages of subtype
260 mixed, alternative, parallel, and digest. Any unknown subtype of type
261 multipart (without a profile entry), will be treated as multipart/mixed.
263 If none of these apply, then
267 Example entries might be:
271 mhshow-show-audio/basic: raw2audio 2>/dev/null | play
272 mhshow-show-image: xv %f
273 mhshow-show-application/PostScript: lpr -Pps
277 When expanding %f and %F escapes, the file names get wrapped in
278 single-quotes automatically.
282 will process each message serially \- it won't start
283 showing the next message until all the commands executed to display the
284 current message have terminated. Although a multipart content may
285 contain advice to display the parts in parallel,
288 .SS "Showing Alternate Character Sets"
289 Because a content of type text might be in a non-ASCII character
292 encounters a \*(lqcharset\*(rq parameter for
293 this content, it checks if your terminal can display this character
296 checks this by first examining the the environment
299 and if not set, taking the character encoding of the current locale.
301 If the character set of text/plain cannot be displayed natively, then
302 the default display method converts the content automatically by
306 iconv -f '<foreign-charset>'
309 Note that if you have a custom `mhshow-show-*' display string, you
310 need to care yourself for converting the encodings.
311 (The foreign charset is available through the %c escape.)
315 needs to be available.
317 `mhshow-charset-*' profile entries are not supported anymore.
318 .SS "Messages of Type message/partial"
320 cannot directly display messages of type partial.
321 You must reassemble them first into a normal message using
323 Check the man page for
326 .SS "External Access"
328 does not automatically retrieve message/external-body parts (anymore),
329 but prints the relevant information to enable the user to retrieve
331 .SS "User Environment"
332 Because the display environment in which
334 operates may vary for
337 will look for the environment variable
339 If present, this specifies the name of an additional
340 user profile which should be read. Hence, when a user logs in on a
341 particular display device, this environment variable should be set to
342 refer to a file containing definitions useful for the given display device.
343 Normally, only entries that deal with the methods to display different
344 content type and subtypes
348 mhshow-show-<type>/<subtype>
353 need be present in this additional profile. Finally,
355 will attempt to consult one other additional user profile,
359 %etcdir%/mhn.defaults
362 which is created automatically during
369 .ta \w'%etcdir%/ExtraBigFileName 'u
370 ^$HOME/.mmh/profile~^The user profile
371 ^$MHSHOW~^Additional profile entries
372 ^%etcdir%/mhn.defaults~^System default MIME profile entries
373 ^%etcdir%/mhl.headers~^The headers template
376 .SH "PROFILE COMPONENTS"
380 .ta \w'ExtraBigProfileName 'u
381 ^Path:~^To determine the user's mail storage
382 ^Current\-Folder:~^To find the default current folder
383 ^Unseen\-Sequence:~^To name sequences denoting unseen messages
384 ^mhshow-show-<type>*~^Template for displaying contents
385 ^Pager:~^Program to use as interactive front\-end
389 mhbuild(1), mhl(1), mhlist(1), mhstore(1), sendfiles(1)
393 .RB ` +folder "' defaults to the current folder"
394 .RB ` msgs "' defaults to cur"
395 .RB ` \-form \ mhl.headers'
400 If a folder is given, it will become the current folder. The last
401 message selected will become the current message.
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