1 .TH MHFIXMSG %manext1% "November 30, 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.
153 applies one transformation unconditionally: it removes an extraneous
154 trailing semicolon from the parameter lists of MIME header fields.
160 to output informational message for each transformation applied.
164 is 0 if all of the requested transformations are performed, or
167 will not decode to binary content, but a request to do so is
168 not considered a failure, and is noted with
170 If a problem is detected with any one of multiple messages such that
171 the return status is non-zero, then none of the messages will be
180 file as the source message, rather than a message from a folder.
181 Only one file argument may be provided. The
185 is an absolute pathname.
186 If the file is \*(lq-\*(rq, then
188 accepts the source message on the standard input stream. If
191 switch is not enabled when using the standard input stream,
193 will not produce a transformed output message.
196 by default, transforms the message in place. If the
198 switch is enabled, then
200 does not modify the input message or file, but instead places its
201 output in the specified file. An outfile name of \*(lq-\*(rq
202 specifies the standard output stream.
208 switch can be used to show what transformations
210 would apply without actually applying them, e.g.,
213 mhfixmsg -outfile /dev/null -verbose
216 As always, this usage obeys any
218 switches in the user's profile.
223 to add a single transformed message to a different folder, e.g.,
226 mhfixmsg -outfile - | \\
228 %nmhlibexecdir%/rcvstore +folder
231 .SS Summary of Applicability
232 The transformations apply to the parts of a message depending on
233 content type and/or encoding as follows:
237 .ta \w'\-fixboundary 'u
238 \-decodetext base64 and quoted-printable encoded text parts
239 \-textcharset text/plain parts
240 \-reformat text parts that are not text/plain
241 \-fixboundary outermost multipart part
242 \-fixcte multipart part
246 .SS "Backup of Original Message/File"
247 If it applies any transformations to a message or file,
252 backs up the original the same way as
256 profile component, if present. If not present,
258 moves the original message to a backup file.
261 switch may be used to override this profile component. The
263 switch disables the use of any
265 profile component and negates all prior
269 .SS "Integration with inc"
271 can be used as an add-hook, as described in %docdir%/README-HOOKS.
272 Note that add-hooks are called from all
274 programs that add a message to a folder, not just
276 Alternatively, a simple shell alias or function can be used to
279 immediately after a successful invocation of
281 One approach could be based on:
284 msgs=`inc -format '%(msg)'` && [ -n "$msgs" ] && scan $msgs && \
285 mhfixmsg -nochangecur $msgs
288 Another approach would rely on adding a sequence to Unseen-Sequence,
291 sets with the newly incorporated messages. Those could then be
294 .SS "Integration with procmail"
295 By way of example, here is an excerpt from a procmailrc file
296 that filters messages through
298 before storing them in the user's
300 folder. It also stores the incoming message in the
302 folder in a filename generated by
304 which is a non-POSIX utility to generate a temporary file.
307 could be called on the message after it is stored.
311 .ta \w'\-fixboundary 'u
312 PATH = %bindir%:$PATH
313 MAILDIR = `mhparam path`
314 #### The Backups directory is relative to MAILDIR.
315 MKSTEMP = 'mkstemp -directory Backups -prefix mhfixmsg'
316 MHFIXMSG = 'mhfixmsg -noverbose -file - -outfile -'
317 STORE = %nmhlibexecdir%/rcvstore
319 :0 w: nmh-workers/procmail.$LOCKEXT
320 * ^TOnmh-workers@nongnu.org
321 | tee `$MKSTEMP` | $MHFIXMSG | $STORE +nmh-workers
327 looks for mhn.defaults in multiple locations: absolute pathnames are
328 accessed directly, tilde expansion is done on usernames, and files are
329 searched for in the user's
331 directory as specified in their profile. If not found there, the directory
332 .RI \*(lq %nmhetcdir% \*(rq
337 .ta \w'%nmhetcdir%/mhn.defaults 'u
338 ^$HOME/\&.mh\(ruprofile~^The user profile
339 ^%nmhetcdir%/mhn.defaults~^Default mhfixmsg conversion entries
341 .SH "PROFILE COMPONENTS"
345 .ta \w'ExtraBigProfileName 'u
346 ^Path:~^To determine the user's nmh directory
347 ^Current\-Folder:~^To find the default current folder
348 ^rmmproc:~^Program to delete original messages or files
365 .RB ` +folder "' defaults to the current folder"
366 .RB ` msgs "' defaults to cur"
367 .RB ` "\-decodetext 8bit"'
368 .RB ` \-notextcharset '
370 .RB ` \-noreplacetextplain '
371 .RB ` \-fixboundary '
377 If a folder is given, it will become the current folder. The last
378 message selected from a folder will become the current message, unless
381 switch is enabled. If the
383 switch or an absolute pathname is used, the context will not be
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