4 .TH MHSHOW %manext1% "%nmhdate%" MH.6.8 [%nmhversion%]
6 mhshow \- display MIME messages
21 .RB [ \-serialonly " | " \-noserialonly ]
28 .RB [ \-check " | " \-nocheck ]
35 command display contents of a MIME (multi-media)
36 message or collection of messages.
39 manipulates multi-media messages as specified in
40 RFC\-2045 thru RFC\-2049. Currently
43 encodings in message bodies, and does not support the encoding of
44 message headers as specified in RFC\-2047.
48 will display all parts of a multipart
56 to particular subparts (of a
57 multipart content) and/or particular content types.
64 to use the specified file as
65 the source message, rather than a message from a folder. If you specify
66 this file as \*(lq-\*(rq, then
68 will accept the source message
69 on the standard input. Note that the file, or input from standard input
70 should be a validly formatted message, just like any other
74 be in mail drop format (to convert a file in
75 mail drop format to a folder of
80 A part specification consists of a series of numbers separated by dots.
81 For example, in a multipart content containing three parts, these
82 would be named as 1, 2, and 3, respectively. If part 2 was also a
83 multipart content containing two parts, these would be named as 2.1 and
84 2.2, respectively. Note that the
86 switch is effective for only
87 messages containing a multipart content. If a message has some other
88 kind of content, or if the part is itself another multipart content, the
90 switch will not prevent the content from being acted upon.
92 A content specification consists of a content type and a subtype.
93 The initial list of \*(lqstandard\*(rq content types and subtypes can
94 be found in RFC\-2046.
96 A list of commonly used contents is briefly reproduced here:
100 .ta \w'application 'u
104 multipart mixed, alternative, digest, parallel
105 message rfc822, partial, external-body
106 application octet-stream, postscript
113 A legal MIME message must contain a subtype specification.
115 To specify a content, regardless of its subtype, just use the
116 name of the content, e.g., \*(lqaudio\*(rq. To specify a specific
117 subtype, separate the two with a slash, e.g., \*(lqaudio/basic\*(rq.
118 Note that regardless of the values given to the `\-type' switch, a
119 multipart content (of any subtype listed above) is always acted upon.
120 Further note that if the `\-type' switch is used, and it is desirable to
121 act on a message/external-body content, then the `\-type' switch must
122 be used twice: once for message/external-body and once for the content
123 externally referenced.
124 .SS "Unseen Sequence"
125 If the profile entry \*(lqUnseen\-Sequence\*(rq is present and
128 will remove each of the messages shown
129 from each sequence named by the profile entry.
130 .SS "Checking the Contents"
135 to check each content for an
136 integrity checksum. If a content has such a checksum (specified as a
137 Content-MD5 header field), then
139 will attempt to verify the
140 integrity of the content.
141 .SS "Showing the Contents"
142 The headers of each message are displayed with the
146 using the standard format file
148 You may specify an alternate format file with the
151 switch. If the format file
153 is specified, then the display
154 of the message headers is suppressed.
156 Next, the contents are extracted from the message and are stored in
157 a temporary file. Usually, the name of the temporary file is the
158 word \*(lqmhshow\*(rq followed by a string of characters. Occasionally,
159 the method used to display a content (described next), requires that
160 the file end in a specific suffix. For example, the
162 command (part of the StarOffice package) can be used to display
163 Microsoft Word content, but it uses the suffix to determine how to display
164 the file. If no suffix is present, the file is not correctly loaded.
165 Similarily, older versions of the
167 command append a \*(lq.ps\*(rq suffix to
168 the filename if one was missing. As a result, these cannot be used to read
169 the default temporary file.
171 To get around this, your profile can contain lines of the form:
174 mhshow-suffix-<type>/<subtype>: <suffix>
180 mhshow-suffix-<type>: <suffix>
183 to specify a suffix which can be automatically added to the temporary
184 file created for a specific content type. For example, the following
185 lines might appear in your profile:
189 mhshow-suffix-text: .txt
190 mhshow-suffix-application/msword: .doc
191 mhshow-suffix-application/PostScript: .ps
195 to automatically append a suffix to the temporary files.
197 The method used to display the different contents in the messages bodies
198 will be determined by a \*(lqdisplay string\*(rq. To find the display
201 will first search your profile for an entry of the form:
204 mhshow-show-<type>/<subtype>
207 to determine the display string. If this isn't found,
209 will search for an entry of the form:
215 to determine the display string.
217 If a display string is found, any escapes (given below) will be expanded.
218 The result will be executed under
219 \*(lq/bin/sh\*(rq, with the standard input
222 The display string may contain the following escapes:
227 %a Insert parameters from Content-Type field
228 %e exclusive execution
229 %f Insert filename containing content
230 %F %e, %f, and stdin is terminal not content
231 %l display listing prior to displaying content
233 %s Insert content subtype
234 %d Insert content description
235 %% Insert the character %
239 For those display strings containing the e- or F-escape,
242 execute at most one of these at any given time. Although the F-escape
243 expands to be the filename containing the content, the e-escape has no
244 expansion as far as the shell is concerned.
248 is display a content, typing QUIT (usually
249 control-\\) will tell
251 to wrap things up immediately.
253 Note that if the content being displayed is multipart, but not one of
254 the subtypes listed above, then the f- and F-escapes expand to multiple
255 filenames, one for each subordinate content. Further, stdin is not
256 redirected from the terminal to the content.
258 If a display string is not found,
260 has the following default values:
264 mhshow-show-text/plain: %l<defaultpager> '%F'
265 mhshow-show-message/rfc822: %lshow \-file '%F'
269 If a subtype of type text doesn't have a profile entry, it will be
270 treated as text/plain.
273 has default methods for handling multipart messages of subtype
274 mixed, alternative, parallel, and digest. Any unknown subtype of type
275 multipart (without a profile entry), will be treated as multipart/mixed.
277 If none of these apply, then
279 will check to see if the message
280 has an application/octet-stream content with parameter \*(lqtype=tar\*(rq.
283 will use an appropriate command. If not,
287 Example entries might be:
291 mhshow-show-audio/basic: raw2audio 2>/dev/null | play
292 mhshow-show-image: xv '%f'
293 mhshow-show-application/PostScript: lpr -Pps
297 Note that when using the f- or F-escape, it's a good idea to use
298 single-quotes around the escape. This prevents misinterpretation by
299 the shell of any funny characters that might be present in the filename.
303 will process each message serially\0--\0it won't start
304 showing the next message until all the commands executed to display the
305 current message have terminated. In the case of a multipart content
306 (of any subtype listed above), the content contains advice indicating if
307 the parts should be displayed serially or in parallel. Because this may
308 cause confusion, particularly on uni-window displays, the
310 switch can be given to tell
312 to never display parts in parallel.
313 .SS "Showing Alternate Character Sets"
314 Because a content of type text might be in a non-ASCII character
317 encounters a \*(lqcharset\*(rq parameter for
318 this content, it checks if your terminal can display this character
321 checks this by examining the the environment
324 If the value of this environment variable is equal
325 to the value of the charset parameter, then
328 display this content without any additional setup. If this environment
331 will assume a value of \*(lqUS-ASCII\*(rq.
332 If the character set cannot be displayed natively, then
334 will look for an entry of the form:
337 mhshow-charset-<charset>
340 which should contain a command creating an environment to render
341 the character set. This command string should containing a single
342 \*(lq%s\*(rq, which will be filled-in with the command to display the
345 Example entries might be:
348 mhshow-charset-iso-8859-1: xterm -fn '-*-*-medium-r-normal-*-*-120-*-*-c-*-iso8859-*' -e %s
354 mhshow-charset-iso-8859-1: '%s'
357 The first example tells
362 appropriate character set for that message content. The second example
365 that your pager (or other program handling that content
366 type) can handle that character set, and that no special processing is
369 Note that many pagers strip off the high-order bit or have problems
370 displaying text with the high-order bit set. However, the pager
372 has support for single-octet character sets. The source
375 is available on many ftp sites carrying free software.
376 In order to view messages sent in the ISO-8859-1 character set using
379 put these lines in your
385 setenv LESSCHARSET latin1
392 to use the ISO-8859-1 definition for
393 determining whether a character is \*(lqnormal\*(rq, \*(lqcontrol\*(lq,
394 or \*(lqbinary\*(rq. The second line tells
397 if it encounters a file that has non-ASCII characters. Then,
403 called automatically. (To handle other single-octet character sets,
406 manual entry for information about the
408 environment variable.)
409 .SS "Messages of Type message/partial"
411 cannot directly display messages of type partial.
412 You must reassemble them first into a normal message using
414 Check the man page for
417 .SS "External Access"
418 For contents of type message/external-body,
420 supports these access-types:
433 For the \*(lqanon-ftp\*(rq and \*(lqftp\*(rq access types,
435 will look for the \*(lqnmh-access-ftp\*(rq
439 nmh-access-ftp: myftp.sh
442 to determine the pathname of a program to perform the FTP retrieval.
444 This program is invoked with these arguments:
448 domain name of FTP-site
454 \*(lqascii\*(rq or \*(lqbinary\*(rq
458 The program should terminate with an exit status of zero if the
459 retrieval is successful, and a non-zero exit status otherwise.
460 .SS "The Content Cache"
463 encounters an external content containing a
464 \*(lqContent-ID:\*(rq field, and if the content allows caching, then
465 depending on the caching behavior of
467 the content might be read from or written to a cache.
469 The caching behavior of
471 is controlled with the
475 switches, which define the policy for reading from,
476 and writing to, the cache, respectively. One of four policies may be
477 specified: \*(lqpublic\*(rq, indicating that
480 of a publically-accessible content cache; \*(lqprivate\*(rq, indicating
483 should make use of the user's private content cache;
484 \*(lqnever\*(rq, indicating that
486 should never make use of
487 caching; and, \*(lqask\*(rq, indicating that
491 There are two directories where contents may be cached: the profile entry
492 \*(lqnmh-cache\*(rq names a directory containing world-readable contents, and,
493 the profile entry \*(lqnmh-private-cache\*(rq names a directory containing
494 private contents. The former should be an absolute (rooted) directory
503 might be used if you didn't care that the cache got wiped after each
504 reboot of the system. The private cache is interpreted relative to the user's
505 mail storage, if not rooted, e.g.,
508 nmh-private-cache: .cache
511 (which is the default value).
512 .SS "User Environment"
513 Because the display environment in which
515 operates may vary for
518 will look for the environment variable
520 If present, this specifies the name of an additional
521 user profile which should be read. Hence, when a user logs in on a
522 particular display device, this environment variable should be set to
523 refer to a file containing definitions useful for the given display device.
524 Normally, only entries that deal with the methods to display different
525 content type and subtypes
529 mhshow-show-<type>/<subtype>
534 need be present in this additional profile. Finally,
536 will attempt to consult one other additional user profile,
540 %etcdir%/mhn.defaults
543 which is created automatically during
550 .ta \w'%etcdir%/ExtraBigFileName 'u
551 ^$HOME/.mmh/profile~^The user profile
552 ^$MHSHOW~^Additional profile entries
553 ^%etcdir%/mhn.defaults~^System default MIME profile entries
554 ^%etcdir%/mhl.headers~^The headers template
557 .SH "PROFILE COMPONENTS"
561 .ta \w'ExtraBigProfileName 'u
562 ^Path:~^To determine the user's mail storage
563 ^Current\-Folder:~^To find the default current folder
564 ^Unseen\-Sequence:~^To name sequences denoting unseen messages
565 ^mhlproc:~^Default program to display message headers
566 ^nmh-access-ftp:~^Program to retrieve contents via FTP
567 ^nmh-cache~^Public directory to store cached external contents
568 ^nmh-private-cache~^Personal directory to store cached external contents
569 ^mhshow-charset-<charset>~^Template for environment to render character sets
570 ^mhshow-show-<type>*~^Template for displaying contents
571 ^Pager:~^Default program to display text/plain content
575 mhbuild(1), mhl(1), mhlist(1), mhstore(1), sendfiles(1)
579 .RB ` +folder "' defaults to the current folder"
580 .RB ` msgs "' defaults to cur"
582 .RB ` \-form mhl.headers '
585 .RB ` \-noserialonly '
591 If a folder is given, it will become the current folder. The last
592 message selected will become the current message.
projects / mmh / blob