5 .TH MHSHOW %manext1% "%nmhdate%" MH.6.8 [%nmhversion%]
7 mhshow \- display MIME messages
22 .RB [ \-serialonly " | " \-noserialonly ]
23 .RB [ \-pause " | " \-nopause ]
30 .RB [ \-check " | " \-nocheck ]
37 command display contents of a MIME (multi-media)
38 message or collection of messages.
41 manipulates multi-media messages as specified in
42 RFC\-2045 thru RFC\-2049. Currently
45 encodings in message bodies, and does not support the encoding of
46 message headers as specified in RFC\-2047.
50 will display all parts of a multipart
58 to particular subparts (of a
59 multipart content) and/or particular content types.
66 to use the specified file as
67 the source message, rather than a message from a folder. If you specify
68 this file as \*(lq-\*(rq, then
70 will accept the source message
71 on the standard input. Note that the file, or input from standard input
72 should be a validly formatted message, just like any other
76 be in mail drop format (to convert a file in
77 mail drop format to a folder of
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 Further note that if the `\-type' switch is used, and it is desirable to
123 act on a message/external-body content, then the `\-type' switch must
124 be used twice: once for message/external-body and once for the content
125 externally referenced.
126 .SS "Unseen Sequence"
127 If the profile entry \*(lqUnseen\-Sequence\*(rq is present and
130 will remove each of the messages shown
131 from each sequence named by the profile entry.
132 .SS "Checking the Contents"
137 to check each content for an
138 integrity checksum. If a content has such a checksum (specified as a
139 Content-MD5 header field), then
141 will attempt to verify the
142 integrity of the content.
143 .SS "Showing the Contents"
144 The headers of each message are displayed with the
148 using the standard format file
150 You may specify an alternate format file with the
153 switch. If the format file
155 is specified, then the display
156 of the message headers is suppressed.
158 Next, the contents are extracted from the message and are stored in
159 a temporary file. Usually, the name of the temporary file is the
160 word \*(lqmhshow\*(rq followed by a string of characters. Occasionally,
161 the method used to display a content (described next), requires that
162 the file end in a specific suffix. For example, the
164 command (part of the StarOffice package) can be used to display
165 Microsoft Word content, but it uses the suffix to determine how to display
166 the file. If no suffix is present, the file is not correctly loaded.
167 Similarily, older versions of the
169 command append a \*(lq.ps\*(rq suffix to
170 the filename if one was missing. As a result, these cannot be used to read
171 the default temporary file.
173 To get around this, your profile can contain lines of the form:
176 mhshow-suffix-<type>/<subtype>: <suffix>
182 mhshow-suffix-<type>: <suffix>
185 to specify a suffix which can be automatically added to the temporary
186 file created for a specific content type. For example, the following
187 lines might appear in your profile:
191 mhshow-suffix-text: .txt
192 mhshow-suffix-application/msword: .doc
193 mhshow-suffix-application/PostScript: .ps
197 to automatically append a suffix to the temporary files.
199 The method used to display the different contents in the messages bodies
200 will be determined by a \*(lqdisplay string\*(rq. To find the display
203 will first search your profile for an entry of the form:
206 mhshow-show-<type>/<subtype>
209 to determine the display string. If this isn't found,
211 will search for an entry of the form:
217 to determine the display string.
219 If a display string is found, any escapes (given below) will be expanded.
220 The result will be executed under
221 \*(lq/bin/sh\*(rq, with the standard input
224 The display string may contain the following escapes:
229 %a Insert parameters from Content-Type field
230 %e exclusive execution
231 %f Insert filename containing content
232 %F %e, %f, and stdin is terminal not content
233 %l display listing prior to displaying content
234 %p %l, and ask for confirmation
235 %s Insert content subtype
236 %d Insert content description
237 %% Insert the character %
241 For those display strings containing the e- or F-escape,
244 execute at most one of these at any given time. Although the F-escape
245 expands to be the filename containing the content, the e-escape has no
246 expansion as far as the shell is concerned.
248 When the p-escape prompts for confirmation, typing INTR (usually
251 not to display that content.
252 The p-escape can be disabled by specifying the switch
256 is display a content, typing QUIT (usually
257 control-\\) will tell
259 to wrap things up immediately.
261 Note that if the content being displayed is multipart, but not one of
262 the subtypes listed above, then the f- and F-escapes expand to multiple
263 filenames, one for each subordinate content. Further, stdin is not
264 redirected from the terminal to the content.
266 If a display string is not found,
268 has several default values:
272 mhshow-show-text/plain: %pmoreproc '%F'
273 mhshow-show-message/rfc822: %pshow -file '%F'
277 If a subtype of type text doesn't have a profile entry, it will be
278 treated as text/plain.
281 has default methods for handling multipart messages of subtype
282 mixed, alternative, parallel, and digest. Any unknown subtype of type
283 multipart (without a profile entry), will be treated as multipart/mixed.
285 If none of these apply, then
287 will check to see if the message
288 has an application/octet-stream content with parameter \*(lqtype=tar\*(rq.
291 will use an appropriate command. If not,
295 Example entries might be:
299 mhshow-show-audio/basic: raw2audio 2>/dev/null | play
300 mhshow-show-image: xv '%f'
301 mhshow-show-application/PostScript: lpr -Pps
305 Note that when using the f- or F-escape, it's a good idea to use
306 single-quotes around the escape. This prevents misinterpretation by
307 the shell of any funny characters that might be present in the filename.
311 will process each message serially\0--\0it won't start
312 showing the next message until all the commands executed to display the
313 current message have terminated. In the case of a multipart content
314 (of any subtype listed above), the content contains advice indicating if
315 the parts should be displayed serially or in parallel. Because this may
316 cause confusion, particularly on uni-window displays, the
318 switch can be given to tell
320 to never display parts in parallel.
321 .SS "Showing Alternate Character Sets"
322 Because a content of type text might be in a non-ASCII character
325 encounters a \*(lqcharset\*(rq parameter for
326 this content, it checks if your terminal can display this character
329 checks this by examining the the environment
332 If the value of this environment variable is equal
333 to the value of the charset parameter, then
336 display this content without any additional setup. If this environment
339 will assume a value of \*(lqUS-ASCII\*(rq.
340 If the character set cannot be displayed natively, then
342 will look for an entry of the form:
345 mhshow-charset-<charset>
348 which should contain a command creating an environment to render
349 the character set. This command string should containing a single
350 \*(lq%s\*(rq, which will be filled-in with the command to display the
353 Example entries might be:
356 mhshow-charset-iso-8859-1: xterm -fn '-*-*-medium-r-normal-*-*-120-*-*-c-*-iso8859-*' -e %s
362 mhshow-charset-iso-8859-1: '%s'
365 The first example tells
370 appropriate character set for that message content. The second example
373 that your pager (or other program handling that content
374 type) can handle that character set, and that no special processing is
377 Note that many pagers strip off the high-order bit or have problems
378 displaying text with the high-order bit set. However, the pager
380 has support for single-octet character sets. The source
383 is available on many ftp sites carrying free software.
384 In order to view messages sent in the ISO-8859-1 character set using
387 put these lines in your
393 setenv LESSCHARSET latin1
400 to use the ISO-8859-1 definition for
401 determining whether a character is \*(lqnormal\*(rq, \*(lqcontrol\*(lq,
402 or \*(lqbinary\*(rq. The second line tells
405 if it encounters a file that has non-ASCII characters. Then, simply
411 called automatically. (To handle other single-octet character sets,
414 manual entry for information about the
416 environment variable.)
417 .SS "Messages of Type message/partial"
419 cannot directly display messages of type partial.
420 You must reassemble them first into a normal message using
422 Check the man page for
425 .SS "External Access"
426 For contents of type message/external-body,
428 supports these access-types:
441 For the \*(lqanon-ftp\*(rq and \*(lqftp\*(rq access types,
443 will look for the \*(lqnmh-access-ftp\*(rq
447 nmh-access-ftp: myftp.sh
450 to determine the pathname of a program to perform the FTP retrieval.
452 This program is invoked with these arguments:
456 domain name of FTP-site
462 \*(lqascii\*(rq or \*(lqbinary\*(rq
466 The program should terminate with an exit status of zero if the
467 retrieval is successful, and a non-zero exit status otherwise.
469 If this entry is not provided, then
472 built-in FTP client to perform the retrieval.
473 .SS "The Content Cache"
476 encounters an external content containing a
477 \*(lqContent-ID:\*(rq field, and if the content allows caching, then
478 depending on the caching behavior of
480 the content might be read from or written to a cache.
482 The caching behavior of
484 is controlled with the
488 switches, which define the policy for reading from,
489 and writing to, the cache, respectively. One of four policies may be
490 specified: \*(lqpublic\*(rq, indicating that
493 of a publically-accessible content cache; \*(lqprivate\*(rq, indicating
496 should make use of the user's private content cache;
497 \*(lqnever\*(rq, indicating that
499 should never make use of
500 caching; and, \*(lqask\*(rq, indicating that
504 There are two directories where contents may be cached: the profile entry
505 \*(lqnmh-cache\*(rq names a directory containing world-readable contents, and,
506 the profile entry \*(lqnmh-private-cache\*(rq names a directory containing
507 private contents. The former should be an absolute (rooted) directory
516 might be used if you didn't care that the cache got wiped after each
517 reboot of the system. The latter is interpreted relative to the user's
518 nmh directory, if not rooted, e.g.,
521 nmh-private-cache: .cache
524 (which is the default value).
525 .SS "User Environment"
526 Because the display environment in which
528 operates may vary for
531 will look for the environment variable
533 If present, this specifies the name of an additional
534 user profile which should be read. Hence, when a user logs in on a
535 particular display device, this environment variable should be set to
536 refer to a file containing definitions useful for the given display device.
537 Normally, only entries that deal with the methods to display different
538 content type and subtypes
542 mhshow-show-<type>/<subtype>
547 need be present in this additional profile. Finally,
549 will attempt to consult one other additional user profile,
553 %etcdir%/mhn.defaults
556 which is created automatically during
563 .ta \w'%etcdir%/ExtraBigFileName 'u
564 ^$HOME/\&.mh\(ruprofile~^The user profile
565 ^$MHSHOW~^Additional profile entries
566 ^%etcdir%/mhn.defaults~^System default MIME profile entries
567 ^%etcdir%/mhl.headers~^The headers template
570 .SH "PROFILE COMPONENTS"
574 .ta \w'ExtraBigProfileName 'u
575 ^Path:~^To determine the user's nmh directory
576 ^Current\-Folder:~^To find the default current folder
577 ^Unseen\-Sequence:~^To name sequences denoting unseen messages
578 ^mhlproc:~^Default program to display message headers
579 ^nmh-access-ftp:~^Program to retrieve contents via FTP
580 ^nmh-cache~^Public directory to store cached external contents
581 ^nmh-private-cache~^Personal directory to store cached external contents
582 ^mhshow-charset-<charset>~^Template for environment to render character sets
583 ^mhshow-show-<type>*~^Template for displaying contents
584 ^moreproc:~^Default program to display text/plain content
588 mhbuild(1), mhl(1), mhlist(1), mhstore(1), sendfiles(1)
592 .RB ` +folder "' defaults to the current folder"
593 .RB ` msgs "' defaults to cur"
595 .RB ` \-form mhl.headers '
599 .RB ` \-noserialonly '
605 If a folder is given, it will become the current folder. The last
606 message selected will become the current message.
projects / mmh / blob