diplodocus.org Git - nmh/blob - man/mhfixmsg.man

   1 .TH MHFIXMSG %manext1% "March 21, 2013" "%nmhversion%"
   2 .\"
   3 .\" %nmhwarning%
   4 .\"
   5 .SH NAME
   6 mhfixmsg \- rewrite MIME messages with various transformations
   7 .SH SYNOPSIS
   8 .HP 5
   9 .na
  10 .B mhfixmsg
  11 .RI [ +folder ]
  12 .RI [ msgs ]
  13 .RB [ \-decodetext
  14 8bit/7bit |
  15 .BR \-nodecodetext ]
  16 .RB [ \-textcodeset
  17 .I codeset
  18 .RB "| " \-notextcodeset ]
  19 .RB [ \-reformat " | " \-noreformat ]
  20 .RB [ \-fixboundary " | " \-nofixboundary ]
  21 .RB [ \-fixcte " | " \-nofixcte ]
  22 .RB [ \-file
  23 .IR file ]
  24 .RB [ \-outfile
  25 .IR outfile ]
  26 .RB [ \-rmmproc
  27 .IR program ]
  28 .RB [ \-normmproc ]
  29 .RB [ \-verbose " | " \-noverbose ]
  30 .RB [ \-version ]
  31 .RB [ \-help ]
  32 .ad
  33 .SH DESCRIPTION
  34 .B mhfixmsg
  35 rewrites MIME messages, applying specific transformations such as
  36 decoding of MIME-encoded message parts and repairing invalid MIME
  37 headers.
  38 .PP
  39 MIME messages are specified in RFC\-2045 to RFC\-2049
  40 (see
  41 .IR mhbuild (1)).
  42 The
  43 .B mhlist
  44 command is invaluable for viewing the content structure of MIME
  45 messages.
  46 .B mhfixmsg
  47 passes non-MIME messages through without any transformations.  If no
  48 transformations apply to a MIME message, the original message or file
  49 is not modified or removed.
  50 .PP
  51 The
  52 .B \-decodetext
  53 switch enables a transformation to decode each base64 and
  54 quoted-printable text message part to the selected 8bit or 7bit
  55 encoding.  If 7bit is selected for a base64 part but it will only fit
  56 8bit, as defined by RFC-2045, then it will be decoded to 8bit
  57 quoted-printable.  Otherwise, if the decoded text would not fit the
  58 selected encoding, the part is not decoded (and a message will be
  59 displayed if
  60 .B \-verbose
  61 is enabled).
  62 .PP
  63 The
  64 .B \-textcodeset
  65 switch specifies that all text/plain parts of the message(s)
  66 should be converted to
  67 .IR codeset .
  68 Codeset conversions require that
  69 .B nmh
  70 be built with
  71 .IR iconv (3).
  72 To convert text parts other than text/plain, an external program can
  73 be used, via the
  74 .B \-reformat
  75 switch.
  76 .PP
  77 The
  78 .B \-reformat
  79 switch enables a transformation for text parts in the message.  For
  80 each text part that is not text/plain and that does not have a
  81 corresponding text/plain in a multipart/alternative part,
  82 .B mhfixmsg
  83 looks for a mhfixmsg-format-text/subtype profile entry that matches
  84 the subtype of the part.  If one is found and can be used to
  85 successfully convert the part to text/plain,
  86 .B mhfixmsg
  87 inserts that text/plain part at the beginning of the containing
  88 multipart/alternative part, if present.  If not, it creates a
  89 multipart/alternative part.
  90 .PP
  91 .B \-reformat
  92 requires a profile entry for each text part subtype to be reformatted.
  93 The mhfixmsg-format-text/subtype profile entries are based on external
  94 conversion programs, and are used the same way that
  95 .B mhshow
  96 uses its mhshow-show-text/subtype entries.  When
  97 .B nmh
  98 is installed, it searches for a conversion program for text/html
  99 content, and if one is found, inserts a mhfixmsg-format-text/html
 100 entry in %etcdir%/mhn.defaults.  An entry of the same name in the
 101 user's profile takes precedence.  The user can add entries for
 102 other text subtypes to their profile.
 103 .PP
 104 The
 105 .B \-fixboundary
 106 switch enables a transformation to repair the boundary portion of the
 107 Content-Type header field of the message to match the boundaries of
 108 the outermost multipart part of the message, if it does not.  That
 109 condition is indicated by a \*(lqbogus multipart content in
 110 message\*(rq error message from
 111 .B mhlist
 112 and other
 113 .B nmh
 114 programs that parse MIME messages.
 115 .PP
 116 The
 117 .B \-fixcte
 118 switch enables a transformation to change the
 119 Content-Transfer-Encoding from an invalid value to 8bit in message
 120 parts with a Content-Type of multipart, as required by RFC 2045,
 121 Section 6.4.  That condition is indicated by a \*(lqmust be encoded in
 122 7bit, 8bit, or binary\*(rq error message from
 123 .B mhlist
 124 and other
 125 .B nmh
 126 programs that parse MIME messages.
 127 .PP
 128 The
 129 .B \-verbose
 130 switch directs
 131 .B mhfixmsg
 132 to output informational message for each transformation applied.
 133 .PP
 134 The
 135 .B \-file
 136 .I file
 137 switch directs
 138 .B mhfixmsg
 139 to use the specified
 140 file as the source message, rather than a message from a folder.
 141 If this file is \*(lq-\*(rq, then
 142 .B mhfixmsg
 143 accepts the source message on the standard input stream.  If
 144 the
 145 .B \-outfile
 146 switch is not enabled when using the standard input stream,
 147 .B mhfixmsg
 148 will not produce a transformed output message.
 149 .PP
 150 .BR mhfixmsg ,
 151 by default, transforms the message in place.  If the
 152 .B \-outfile
 153 switch is enabled, then
 154 .B mhfixmsg
 155 does not modify the input message or file, but instead places its
 156 output in the specified file.  An outfile name of \*(lq-\*(rq
 157 specifies the standard output stream.
 158 .PP
 159 Combined with the
 160 .B \-verbose
 161 switch, the
 162 .B \-outfile
 163 switch can be used to show what transformations
 164 .B mhfixmsg
 165 would apply without actually applying them, e.g.,
 166 .PP
 167 .RS 5
 168 mhfixmsg -outfile /dev/null -verbose
 169 .RE
 170 .PP
 171 As always, this usage obeys any
 172 .B mhfixmsg
 173 switches in the user's profile.
 174 .PP
 175 .B \-outfile
 176 can be combined with
 177 .B rcvstore
 178 to add a single transformed message to a different folder, e.g.,
 179 .PP
 180 .RS 5
 181 mhfixmsg -outfile - | \\
 182 .RS 0
 183 %libdir%/rcvstore +folder
 184 .RE
 185 .RE
 186 .SS Summary of Applicability
 187 The transformations apply to the parts of a message depending on
 188 content type and/or encoding as follows:
 189 .PP
 190 .RS 5
 191 .nf
 192 .ta \w'\-fixboundary 'u
 193 \-decodetext   base64 and quoted-printable encoded text parts
 194 \-textcodeset  text/plain parts
 195 \-reformat     text parts that are not text/plain
 196 \-fixboundary  outermost multipart part
 197 \-fixcte       multipart part
 198 .fi
 199 .RE
 200 .PP
 201 .SS "Backup of Original Message/File"
 202 If it applies any transformations to a message or file,
 203 and the
 204 .B \-outfile
 205 switch is not used,
 206 .B mhfixmsg
 207 backs up the original the same way as
 208 .BR rmm .
 209 That is, it uses the
 210 .I rmmproc
 211 profile component, if present.  If not present,
 212 .B mhfixmsg
 213 moves the original message to a backup file.
 214 The
 215 .B \-rmmproc
 216 switch may be used to override this profile component.  The
 217 .B \-normmproc
 218 switch disables the use of any
 219 .I rmmproc
 220 profile component and negates all prior
 221 .B \-rmmproc
 222 switches.
 223 .PP
 224 .SS "Integration with procmail"
 225 By way of example, here is an excerpt from a procmailrc file
 226 that filters messages through
 227 .B mhfixmsg
 228 before storing them in the user's
 229 .I nmh-workers
 230 folder.  It also stores the incoming message in the
 231 .I Backups
 232 folder in a filename generated by
 233 .BR mktemp ,
 234 which is a non-POSIX utility to generate a temporary file.
 235 If you do not have that utility, then the
 236 .BR mkstemp (3)
 237 function could form the basis for a substitute.  Or,
 238 .B mhfixmsg
 239 could be called on the message after it is stored.
 240 .PP
 241 .RS 5
 242 .nf
 243 .ta \w'\-fixboundary 'u
 244 PATH = %bindir%:$PATH
 245 MAILDIR = `mhparam path`
 246 MKTEMP = 'mktemp Backups/mhfixmsg.XXXXXXXX'
 247 MHFIXMSG = 'mhfixmsg -noverbose -file - -outfile -'
 248 STORE = %libdir%/rcvstore
 249
 250 :0 w: nmh-worker/procmail.$LOCKEXT
 251 * ^TOnmh-workers@nongnu.org
 252 | tee `$MKTEMP` | $MHFIXMSG | $STORE +nmh-workers
 253 .fi
 254 .RE
 255 .PP
 256 .SH FILES
 257 .B mhfixmsg
 258 looks for mhn.defaults in multiple locations: absolute pathnames are
 259 accessed directly, tilde expansion is done on usernames, and files are
 260 searched for in the user's
 261 .I Mail
 262 directory as specified in their profile.  If not found there, the directory
 263 .RI \*(lq %etcdir% \*(rq
 264 is checked.
 265 .PP
 266 .fc ^ ~
 267 .nf
 268 .ta \w'%etcdir%/mhn.defaults  'u
 269 ^$HOME/\&.mh\(ruprofile~^The user profile
 270 ^%etcdir%/mhn.defaults~^Default mhfixmsg conversion entries
 271 .fi
 272 .SH "PROFILE COMPONENTS"
 273 .fc ^ ~
 274 .nf
 275 .ta 2.4i
 276 .ta \w'ExtraBigProfileName  'u
 277 ^Path:~^To determine the user's nmh directory
 278 ^Current\-Folder:~^To find the default current folder
 279 ^rmmproc:~^Program to delete original messages or files
 280 .fi
 281 .SH "SEE ALSO"
 282 .IR mh-profile (5),
 283 .IR mhbuild (1),
 284 .IR mhlist (1),
 285 .IR mhshow (1),
 286 .IR mkstemp (3),
 287 .IR procmail (1),
 288 .IR procmailrc (5),
 289 .IR rcvstore (1),
 290 .IR rmm (1)
 291 .SH DEFAULTS
 292 .nf
 293 .RB ` +folder "' defaults to the current folder"
 294 .RB ` msgs "' defaults to cur"
 295 .RB ` "\-decodetext 8bit"'
 296 .RB ` \-notextcodeset '
 297 .RB ` \-reformat '
 298 .RB ` \-fixboundary '
 299 .RB ` \-fixcte '
 300 .RB ` \-noverbose '
 301 .fi
 302 .SH CONTEXT
 303 If a folder is given, it will become the current folder.  The last
 304 message selected from a folder will become the current message.  If
 305 the
 306 .B \-file
 307 switch is used, the context will not be modified.