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

   1 .TH MHFIXMSG %manext1% "May 4, 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 When the
  64 .B \-decodetext
  65 switch is enabled, each carriage return character that precedes a
  66 linefeed character is removed from ASCII-encoded text parts.
  67 .PP
  68 The
  69 .B \-textcodeset
  70 switch specifies that all text/plain parts of the message(s)
  71 should be converted to
  72 .IR codeset .
  73 Codeset conversions require that
  74 .B nmh
  75 be built with
  76 .IR iconv (3).
  77 To convert text parts other than text/plain, an external program can
  78 be used, via the
  79 .B \-reformat
  80 switch.
  81 .PP
  82 The
  83 .B \-reformat
  84 switch enables a transformation for text parts in the message.  For
  85 each text part that is not text/plain and that does not have a
  86 corresponding text/plain in a multipart/alternative part,
  87 .B mhfixmsg
  88 looks for a mhfixmsg-format-text/subtype profile entry that matches
  89 the subtype of the part.  If one is found and can be used to
  90 successfully convert the part to text/plain,
  91 .B mhfixmsg
  92 inserts that text/plain part at the beginning of the containing
  93 multipart/alternative part, if present.  If not, it creates a
  94 multipart/alternative part.
  95 .PP
  96 .B \-reformat
  97 requires a profile entry for each text part subtype to be reformatted.
  98 The mhfixmsg-format-text/subtype profile entries are based on external
  99 conversion programs, and are used the same way that
 100 .B mhshow
 101 uses its mhshow-show-text/subtype entries.  When
 102 .B nmh
 103 is installed, it searches for a conversion program for text/html
 104 content, and if one is found, inserts a mhfixmsg-format-text/html
 105 entry in %etcdir%/mhn.defaults.  An entry of the same name in the
 106 user's profile takes precedence.  The user can add entries for
 107 other text subtypes to their profile.
 108 .PP
 109 The
 110 .B \-fixboundary
 111 switch enables a transformation to repair the boundary portion of the
 112 Content-Type header field of the message to match the boundaries of
 113 the outermost multipart part of the message, if it does not.  That
 114 condition is indicated by a \*(lqbogus multipart content in
 115 message\*(rq error message from
 116 .B mhlist
 117 and other
 118 .B nmh
 119 programs that parse MIME messages.
 120 .PP
 121 The
 122 .B \-fixcte
 123 switch enables a transformation to change the
 124 Content-Transfer-Encoding from an invalid value to 8bit in message
 125 parts with a Content-Type of multipart, as required by RFC 2045,
 126 Section 6.4.  That condition is indicated by a \*(lqmust be encoded in
 127 7bit, 8bit, or binary\*(rq error message from
 128 .B mhlist
 129 and other
 130 .B nmh
 131 programs that parse MIME messages.
 132 .PP
 133 The
 134 .B \-verbose
 135 switch directs
 136 .B mhfixmsg
 137 to output informational message for each transformation applied.
 138 .PP
 139 The
 140 .B \-file
 141 .I file
 142 switch directs
 143 .B mhfixmsg
 144 to use the specified
 145 file as the source message, rather than a message from a folder.
 146 If this file is \*(lq-\*(rq, then
 147 .B mhfixmsg
 148 accepts the source message on the standard input stream.  If
 149 the
 150 .B \-outfile
 151 switch is not enabled when using the standard input stream,
 152 .B mhfixmsg
 153 will not produce a transformed output message.
 154 .PP
 155 .BR mhfixmsg ,
 156 by default, transforms the message in place.  If the
 157 .B \-outfile
 158 switch is enabled, then
 159 .B mhfixmsg
 160 does not modify the input message or file, but instead places its
 161 output in the specified file.  An outfile name of \*(lq-\*(rq
 162 specifies the standard output stream.
 163 .PP
 164 Combined with the
 165 .B \-verbose
 166 switch, the
 167 .B \-outfile
 168 switch can be used to show what transformations
 169 .B mhfixmsg
 170 would apply without actually applying them, e.g.,
 171 .PP
 172 .RS 5
 173 mhfixmsg -outfile /dev/null -verbose
 174 .RE
 175 .PP
 176 As always, this usage obeys any
 177 .B mhfixmsg
 178 switches in the user's profile.
 179 .PP
 180 .B \-outfile
 181 can be combined with
 182 .B rcvstore
 183 to add a single transformed message to a different folder, e.g.,
 184 .PP
 185 .RS 5
 186 mhfixmsg -outfile - | \\
 187 .RS 0
 188 %libdir%/rcvstore +folder
 189 .RE
 190 .RE
 191 .SS Summary of Applicability
 192 The transformations apply to the parts of a message depending on
 193 content type and/or encoding as follows:
 194 .PP
 195 .RS 5
 196 .nf
 197 .ta \w'\-fixboundary 'u
 198 \-decodetext   base64 and quoted-printable encoded text parts
 199 \-textcodeset  text/plain parts
 200 \-reformat     text parts that are not text/plain
 201 \-fixboundary  outermost multipart part
 202 \-fixcte       multipart part
 203 .fi
 204 .RE
 205 .PP
 206 .SS "Backup of Original Message/File"
 207 If it applies any transformations to a message or file,
 208 and the
 209 .B \-outfile
 210 switch is not used,
 211 .B mhfixmsg
 212 backs up the original the same way as
 213 .BR rmm .
 214 That is, it uses the
 215 .I rmmproc
 216 profile component, if present.  If not present,
 217 .B mhfixmsg
 218 moves the original message to a backup file.
 219 The
 220 .B \-rmmproc
 221 switch may be used to override this profile component.  The
 222 .B \-normmproc
 223 switch disables the use of any
 224 .I rmmproc
 225 profile component and negates all prior
 226 .B \-rmmproc
 227 switches.
 228 .PP
 229 .SS "Integration with procmail"
 230 By way of example, here is an excerpt from a procmailrc file
 231 that filters messages through
 232 .B mhfixmsg
 233 before storing them in the user's
 234 .I nmh-workers
 235 folder.  It also stores the incoming message in the
 236 .I Backups
 237 folder in a filename generated by
 238 .BR mktemp ,
 239 which is a non-POSIX utility to generate a temporary file.
 240 If you do not have that utility, then the
 241 .BR mkstemp (3)
 242 function could form the basis for a substitute.  Or,
 243 .B mhfixmsg
 244 could be called on the message after it is stored.
 245 .PP
 246 .RS 5
 247 .nf
 248 .ta \w'\-fixboundary 'u
 249 PATH = %bindir%:$PATH
 250 MAILDIR = `mhparam path`
 251 MKTEMP = 'mktemp Backups/mhfixmsg.XXXXXXXX'
 252 MHFIXMSG = 'mhfixmsg -noverbose -file - -outfile -'
 253 STORE = %libdir%/rcvstore
 254
 255 :0 w: nmh-worker/procmail.$LOCKEXT
 256 * ^TOnmh-workers@nongnu.org
 257 | tee `$MKTEMP` | $MHFIXMSG | $STORE +nmh-workers
 258 .fi
 259 .RE
 260 .PP
 261 .SH FILES
 262 .B mhfixmsg
 263 looks for mhn.defaults in multiple locations: absolute pathnames are
 264 accessed directly, tilde expansion is done on usernames, and files are
 265 searched for in the user's
 266 .I Mail
 267 directory as specified in their profile.  If not found there, the directory
 268 .RI \*(lq %etcdir% \*(rq
 269 is checked.
 270 .PP
 271 .fc ^ ~
 272 .nf
 273 .ta \w'%etcdir%/mhn.defaults  'u
 274 ^$HOME/\&.mh\(ruprofile~^The user profile
 275 ^%etcdir%/mhn.defaults~^Default mhfixmsg conversion entries
 276 .fi
 277 .SH "PROFILE COMPONENTS"
 278 .fc ^ ~
 279 .nf
 280 .ta 2.4i
 281 .ta \w'ExtraBigProfileName  'u
 282 ^Path:~^To determine the user's nmh directory
 283 ^Current\-Folder:~^To find the default current folder
 284 ^rmmproc:~^Program to delete original messages or files
 285 .fi
 286 .SH "SEE ALSO"
 287 .IR mh-profile (5),
 288 .IR mhbuild (1),
 289 .IR mhlist (1),
 290 .IR mhshow (1),
 291 .IR mkstemp (3),
 292 .IR procmail (1),
 293 .IR procmailrc (5),
 294 .IR rcvstore (1),
 295 .IR rmm (1)
 296 .SH DEFAULTS
 297 .nf
 298 .RB ` +folder "' defaults to the current folder"
 299 .RB ` msgs "' defaults to cur"
 300 .RB ` "\-decodetext 8bit"'
 301 .RB ` \-notextcodeset '
 302 .RB ` \-reformat '
 303 .RB ` \-fixboundary '
 304 .RB ` \-fixcte '
 305 .RB ` \-noverbose '
 306 .fi
 307 .SH CONTEXT
 308 If a folder is given, it will become the current folder.  The last
 309 message selected from a folder will become the current message.  If
 310 the
 311 .B \-file
 312 switch is used, the context will not be modified.