1 .TH MHFIXMSG %manext1% "November 19, 2014" "%nmhversion%"
6 mhfixmsg \- rewrite MIME messages with various transformations
13 .IR "absolute pathname" " | "
21 .RB "| " \-notextcharset ]
22 .RB [ \-reformat " | " \-noreformat ]
23 .RB [ \-replacetextplain " | " \-noreplacetextplain ]
24 .RB [ \-fixboundary " | " \-nofixboundary ]
25 .RB [ \-fixcte " | " \-nofixcte ]
31 .RB [ \-changecur " | " \-nochangecur ]
32 .RB [ \-verbose " | " \-noverbose ]
38 rewrites MIME messages, applying specific transformations such as
39 decoding of MIME-encoded message parts and repairing invalid MIME
42 MIME messages are specified in RFC 2045 to RFC 2049
47 command is invaluable for viewing the content structure of MIME
50 passes non-MIME messages through without any transformations. If no
51 transformations apply to a MIME message, the original message or file
52 is not modified or removed.
56 switch enables a transformation to decode each base64 and
57 quoted-printable text message part to the selected 8bit or 7bit
58 encoding. If 7bit is selected for a base64 part but it will only fit
59 8bit, as defined by RFC 2045, then it will be decoded to 8bit
60 quoted-printable. Otherwise, if the decoded text would not fit the
61 selected encoding, the part is not decoded (and a message will be
68 switch is enabled, each carriage return character that precedes a
69 linefeed character is removed from text parts encoded in ASCII,
70 ISO-8859-x, UTF-8, or Windows-12xx.
74 switch specifies that all text/plain parts of the message(s)
75 should be converted to
77 Charset conversions require that
83 man page for how determine whether your
85 installation includes that.
86 To convert text parts other than text/plain, an external program can
93 switch enables a transformation for text parts in the message. For
94 each text part that is not text/plain and that does not have a
95 corresponding text/plain in a multipart/alternative part,
97 looks for a mhfixmsg-format-text/subtype profile entry that matches
98 the subtype of the part. If one is found and can be used to
99 successfully convert the part to text/plain,
101 inserts that text/plain part at the beginning of the containing
102 multipart/alternative part, if present. If not, it creates a
103 multipart/alternative part.
106 .B \-replacetextplain
107 switch broadens the applicability of
109 by always replacing a corresponding text/plain part, if one exists.
112 if enabled, the replacement will be shown as two steps: a removal of
113 the text/plain part followed by the usual insertion of a new part.
116 requires a profile entry for each text part subtype to be reformatted.
117 The mhfixmsg-format-text/subtype profile entries are based on external
118 conversion programs, and are used the same way that
120 uses its mhshow-show-text/subtype entries. When
122 is installed, it searches for a conversion program for text/html
123 content, and if one is found, inserts a mhfixmsg-format-text/html
124 entry in %nmhetcdir%/mhn.defaults. An entry of the same name in the
125 user's profile takes precedence. The user can add entries for
126 other text subtypes to their profile.
130 switch enables a transformation to repair the boundary portion of the
131 Content-Type header field of the message to match the boundaries of
132 the outermost multipart part of the message, if it does not. That
133 condition is indicated by a \*(lqbogus multipart content in
134 message\*(rq error message from
138 programs that parse MIME messages.
142 switch enables a transformation to change the
143 Content-Transfer-Encoding from an invalid value to 8bit in message
144 parts with a Content-Type of multipart, as required by RFC 2045,
145 Section 6.4. That condition is indicated by a \*(lqmust be encoded in
146 7bit, 8bit, or binary\*(rq error message from
150 programs that parse MIME messages.
156 to output informational message for each transformation applied.
159 is 0 if all of the requested transformations are performed, or
162 will not decode to binary content, but a request to do so is
163 not considered a failure, and is noted with
172 file as the source message, rather than a message from a folder.
173 Only one file argument may be provided. The
177 is an absolute pathname.
178 If the file is \*(lq-\*(rq, then
180 accepts the source message on the standard input stream. If
183 switch is not enabled when using the standard input stream,
185 will not produce a transformed output message.
188 by default, transforms the message in place. If the
190 switch is enabled, then
192 does not modify the input message or file, but instead places its
193 output in the specified file. An outfile name of \*(lq-\*(rq
194 specifies the standard output stream.
200 switch can be used to show what transformations
202 would apply without actually applying them, e.g.,
205 mhfixmsg -outfile /dev/null -verbose
208 As always, this usage obeys any
210 switches in the user's profile.
215 to add a single transformed message to a different folder, e.g.,
218 mhfixmsg -outfile - | \\
220 %nmhlibexecdir%/rcvstore +folder
223 .SS Summary of Applicability
224 The transformations apply to the parts of a message depending on
225 content type and/or encoding as follows:
229 .ta \w'\-fixboundary 'u
230 \-decodetext base64 and quoted-printable encoded text parts
231 \-textcharset text/plain parts
232 \-reformat text parts that are not text/plain
233 \-fixboundary outermost multipart part
234 \-fixcte multipart part
238 .SS "Backup of Original Message/File"
239 If it applies any transformations to a message or file,
244 backs up the original the same way as
248 profile component, if present. If not present,
250 moves the original message to a backup file.
253 switch may be used to override this profile component. The
255 switch disables the use of any
257 profile component and negates all prior
261 .SS "Integration with inc"
263 can be used as an add-hook, as described in %docdir%/README-HOOKS.
264 Note that add-hooks are called from all
266 programs that add a message to a folder, not just
268 Alternatively, a simple shell alias or function can be used to
271 immediately after a successful invocation of
273 One approach could be based on:
276 msgs=`inc -format '%(msg)'` && [ -n "$msgs" ] && scan $msgs && \
277 mhfixmsg -nochangecur $msgs
280 Another approach would rely on adding a sequence to Unseen-Sequence,
283 sets with the newly incorporated messages. Those could then be
286 .SS "Integration with procmail"
287 By way of example, here is an excerpt from a procmailrc file
288 that filters messages through
290 before storing them in the user's
292 folder. It also stores the incoming message in the
294 folder in a filename generated by
296 which is a non-POSIX utility to generate a temporary file.
299 could be called on the message after it is stored.
303 .ta \w'\-fixboundary 'u
304 PATH = %bindir%:$PATH
305 MAILDIR = `mhparam path`
306 #### The Backups directory is relative to MAILDIR.
307 MKSTEMP = 'mkstemp -directory Backups -prefix mhfixmsg'
308 MHFIXMSG = 'mhfixmsg -noverbose -file - -outfile -'
309 STORE = %nmhlibexecdir%/rcvstore
311 :0 w: nmh-workers/procmail.$LOCKEXT
312 * ^TOnmh-workers@nongnu.org
313 | tee `$MKSTEMP` | $MHFIXMSG | $STORE +nmh-workers
319 looks for mhn.defaults in multiple locations: absolute pathnames are
320 accessed directly, tilde expansion is done on usernames, and files are
321 searched for in the user's
323 directory as specified in their profile. If not found there, the directory
324 .RI \*(lq %nmhetcdir% \*(rq
329 .ta \w'%nmhetcdir%/mhn.defaults 'u
330 ^$HOME/\&.mh\(ruprofile~^The user profile
331 ^%nmhetcdir%/mhn.defaults~^Default mhfixmsg conversion entries
333 .SH "PROFILE COMPONENTS"
337 .ta \w'ExtraBigProfileName 'u
338 ^Path:~^To determine the user's nmh directory
339 ^Current\-Folder:~^To find the default current folder
340 ^rmmproc:~^Program to delete original messages or files
357 .RB ` +folder "' defaults to the current folder"
358 .RB ` msgs "' defaults to cur"
359 .RB ` "\-decodetext 8bit"'
360 .RB ` \-notextcharset '
362 .RB ` \-noreplacetextplain '
363 .RB ` \-fixboundary '
369 If a folder is given, it will become the current folder. The last
370 message selected from a folder will become the current message, unless
373 switch is enabled. If the
375 switch or an absolute pathname is used, the context will not be
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