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

   1 .TH MHFIXMSG %manext1% "March 18, 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 the decoded text would not fit the selected encoding as
  56 defined by RFC-2045, the part is not decoded.
  57 .PP
  58 The
  59 .B \-textcodeset
  60 switch specifies that all text/plain parts of the message(s)
  61 should be converted to
  62 .IR codeset .
  63 Codeset conversions require that
  64 .B nmh
  65 be built with
  66 .IR iconv (3).
  67 To convert text parts other than text/plain, an external program can
  68 be used, via the
  69 .B \-reformat
  70 switch.
  71 .PP
  72 The
  73 .B \-reformat
  74 switch enables a transformation for text parts in the message.  For
  75 each text part that is not text/plain and that does not have a
  76 corresponding text/plain in a multipart/alternative part,
  77 .B mhfixmsg
  78 looks for a mhfixmsg-format-text/subtype profile entry that matches
  79 the subtype of the part.  If one is found and can be used to
  80 successfully convert the part to text/plain,
  81 .B mhfixmsg
  82 inserts that text/plain part at the beginning of the containing
  83 multipart/alternative part, if present.  If not, it creates a
  84 multipart/alternative part.
  85 .PP
  86 .B \-reformat
  87 requires a profile entry for each text part subtype to be reformatted.
  88 The mhfixmsg-format-text/subtype profile entries are based on external
  89 conversion programs, and are used the same way that
  90 .B mhshow
  91 uses its mhshow-show-text/subtype entries.  When
  92 .B nmh
  93 is installed, it searches for a conversion program for text/html
  94 content, and if one is found, inserts a mhfixmsg-format-text/html
  95 entry in %etcdir%/mhn.defaults.  An entry of the same name in the
  96 user's profile takes precedence.  The user can add entries for
  97 other text subtypes to their profile.
  98 .PP
  99 The
 100 .B \-fixboundary
 101 switch enables a transformation to repair the boundary portion of the
 102 Content-Type header field of the message to match the boundaries of
 103 the outermost multipart part of the message, if it does not.  That
 104 condition is indicated by a \*(lqbogus multipart content in
 105 message\*(rq error message from
 106 .B mhlist
 107 and other
 108 .B nmh
 109 programs that parse MIME messages.
 110 .PP
 111 The
 112 .B \-fixcte
 113 switch enables a transformation to change the
 114 Content-Transfer-Encoding from an invalid value to 8bit in message
 115 parts with a Content-Type of multipart, as required by RFC 2045,
 116 Section 6.4.  That condition is indicated by a \*(lqmust be encoded in
 117 7bit, 8bit, or binary\*(rq error message from
 118 .B mhlist
 119 and other
 120 .B nmh
 121 programs that parse MIME messages.
 122 .PP
 123 The
 124 .B \-verbose
 125 switch directs
 126 .B mhfixmsg
 127 to output informational message for each transformation applied.
 128 .PP
 129 The
 130 .B \-file
 131 .I file
 132 switch directs
 133 .B mhfixmsg
 134 to use the specified
 135 file as the source message, rather than a message from a folder.
 136 If this file is \*(lq-\*(rq, then
 137 .B mhfixmsg
 138 accepts the source message on the standard input stream.  If
 139 the
 140 .B \-outfile
 141 switch is not enabled when using the standard input stream,
 142 .B mhfixmsg
 143 will not produce a transformed output message.
 144 .PP
 145 .BR mhfixmsg ,
 146 by default, transforms the message in place.  If the
 147 .B \-outfile
 148 switch is enabled, then
 149 .B mhfixmsg
 150 does not modify the input message or file, but instead places its
 151 output in the specified file.  An outfile name of \*(lq-\*(rq
 152 specifies the standard output stream.
 153 .PP
 154 Combined with the
 155 .B \-verbose
 156 switch, the
 157 .B \-outfile
 158 switch can be used to show what transformations
 159 .B mhfixmsg
 160 would apply without actually applying them, e.g.,
 161 .PP
 162 .RS 5
 163 mhfixmsg -outfile /dev/null -verbose
 164 .RE
 165 .PP
 166 As always, this usage obeys any
 167 .B mhfixmsg
 168 switches in the user's profile.
 169 .PP
 170 .B \-outfile
 171 can be combined with
 172 .B rcvstore
 173 to add a single transformed message to a different folder, e.g.,
 174 .PP
 175 .RS 5
 176 mhfixmsg -outfile - | \\
 177 .RS 0
 178 %libdir%/rcvstore +folder
 179 .RE
 180 .RE
 181 .SS Summary of Applicability
 182 The transformations apply to the parts of a message depending on
 183 content type and/or encoding as follows:
 184 .PP
 185 .RS 5
 186 .nf
 187 .ta \w'\-fixboundary 'u
 188 \-decodetext   base64 and quoted-printable encoded text parts
 189 \-textcodeset  text/plain parts
 190 \-reformat     text parts that are not text/plain
 191 \-fixboundary  outermost multipart part
 192 \-fixcte       multipart part
 193 .fi
 194 .RE
 195 .PP
 196 .SS "Backup of Original Message/File"
 197 If it applies any transformations to a message or file,
 198 and the
 199 .B \-outfile
 200 switch is not used,
 201 .B mhfixmsg
 202 backs up the original the same way as
 203 .BR rmm .
 204 That is, it uses the
 205 .I rmmproc
 206 profile component, if present.  If not present,
 207 .B mhfixmsg
 208 moves the original message to a backup file.
 209 The
 210 .B \-rmmproc
 211 switch may be used to override this profile component.  The
 212 .B \-normmproc
 213 switch disables the use of any
 214 .I rmmproc
 215 profile component and negates all prior
 216 .B \-rmmproc
 217 switches.
 218 .PP
 219 .SS "Integration with procmail"
 220 By way of example, here is an excerpt from a procmailrc file
 221 that filters messages through
 222 .B mhfixmsg
 223 before storing them in the user's
 224 .I nmh-workers
 225 folder.  It also stores the incoming message in the
 226 .I Backups
 227 folder in a filename generated by
 228 .BR mktemp ,
 229 which is a non-POSIX utility to generate a temporary file.
 230 If you do not have that utility, then the
 231 .BR mkstemp (3)
 232 function could form the basis for a substitute.  Or,
 233 .B mhfixmsg
 234 could be called on the message after it is stored.
 235 .PP
 236 .RS 5
 237 .nf
 238 .ta \w'\-fixboundary 'u
 239 PATH = %bindir%:$PATH
 240 MAILDIR = `mhparam path`
 241 MKTEMP = 'mktemp Backups/mhfixmsg.XXXXXXXX'
 242 MHFIXMSG = 'mhfixmsg -noverbose -file - -outfile -'
 243 STORE = %libdir%/rcvstore
 244
 245 :0 w: nmh-worker/procmail.$LOCKEXT
 246 * ^TOnmh-workers@nongnu.org
 247 | tee `$MKTEMP` | $MHFIXMSG | $STORE +nmh-workers
 248 .fi
 249 .RE
 250 .PP
 251 .SH FILES
 252 .fc ^ ~
 253 .nf
 254 .ta \w'%etcdir%/mhn.defaults  'u
 255 ^$HOME/\&.mh\(ruprofile~^The user profile
 256 ^%etcdir%/mhn.defaults~^Default mhfixmsg conversion entries
 257 .fi
 258 .SH "PROFILE COMPONENTS"
 259 .fc ^ ~
 260 .nf
 261 .ta 2.4i
 262 .ta \w'ExtraBigProfileName  'u
 263 ^Path:~^To determine the user's nmh directory
 264 ^Current\-Folder:~^To find the default current folder
 265 ^rmmproc:~^Program to delete original messages or files
 266 .fi
 267 .SH "SEE ALSO"
 268 .IR mh-profile (5),
 269 .IR mhbuild (1),
 270 .IR mhlist (1),
 271 .IR mhshow (1),
 272 .IR mkstemp (3),
 273 .IR procmail (1),
 274 .IR procmailrc (5),
 275 .IR rcvstore (1),
 276 .IR rmm (1)
 277 .SH DEFAULTS
 278 .nf
 279 .RB ` +folder "' defaults to the current folder"
 280 .RB ` msgs "' defaults to cur"
 281 .RB ` "\-decodetext 8bit"'
 282 .RB ` \-notextcodeset '
 283 .RB ` \-reformat '
 284 .RB ` \-fixboundary '
 285 .RB ` \-fixcte '
 286 .RB ` \-noverbose '
 287 .fi
 288 .SH CONTEXT
 289 If a folder is given, it will become the current folder.  The last
 290 message selected from a folder will become the current message.  If
 291 the
 292 .B \-file
 293 switch is used, the context will not be modified.