-.TH MHFIXMSG %manext1% "November 19, 2014" "%nmhversion%"
+.TH MHFIXMSG %manext1% "October 3, 2016" "%nmhversion%"
.\"
.\" %nmhwarning%
.\"
.HP 5
.na
.B mhfixmsg
+.RB [ \-help ]
+.RB [ \-version ]
.RI [ +folder ]
.RI [ msgs " | "
.IR "absolute pathname" " | "
.RB \-file
.IR file ]
.RB [ \-decodetext
-8bit/7bit |
+8bit|7bit|binary |
.BR \-nodecodetext ]
+.RB [ \-decodetypes
+.IR "type/[subtype][,...]" ]
+.RB [ \-crlflinebreaks " | " \-nocrlflinebreaks ]
.RB [ \-textcharset
.I charset
.RB "| " \-notextcharset ]
.RB [ \-replacetextplain " | " \-noreplacetextplain ]
.RB [ \-fixboundary " | " \-nofixboundary ]
.RB [ \-fixcte " | " \-nofixcte ]
+.RB [ \-fixtype
+.IR mimetype ]
.RB [ \-outfile
.IR outfile ]
.RB [ \-rmmproc
.RB [ \-normmproc ]
.RB [ \-changecur " | " \-nochangecur ]
.RB [ \-verbose " | " \-noverbose ]
-.RB [ \-version ]
-.RB [ \-help ]
.ad
.SH DESCRIPTION
.B mhfixmsg
.B mhfixmsg
passes non-MIME messages through without any transformations. If no
transformations apply to a MIME message, the original message or file
-is not modified or removed.
+is not modified or removed. Thus,
+.B mhfixmsg
+can safely be run multiple times on a message.
.PP
The
.B \-decodetext
switch enables a transformation to decode each base64 and
-quoted-printable text message part to the selected 8bit or 7bit
-encoding. If 7bit is selected for a base64 part but it will only fit
+quoted-printable text message part to the selected 8bit, 7bit, or
+binary encoding.
+If 7bit is selected for a base64 part but it will only fit
8bit, as defined by RFC 2045, then it will be decoded to 8bit
-quoted-printable. Otherwise, if the decoded text would not fit the
-selected encoding, the part is not decoded (and a message will be
+quoted-printable.
+Similarly, with 8bit, if the decoded text would be binary,
+then the part is not decoded (and a message will be
displayed if
.B \-verbose
-is enabled).
+is enabled). Note that
+.B \-decodetext
+binary can produce messages that are not RFC 2045 compliant.
.PP
When the
.B \-decodetext
ISO-8859-x, UTF-8, or Windows-12xx.
.PP
The
+.B \-decodetypes
+switch specifies the message parts, by type and optionally subtype,
+to which
+.B \-decodetext
+applies. Its argument is a comma-separated list of type/subtype
+elements. If an element does not contain a subtype, then
+.B \-decodetext
+applies to all subtypes of the type. The default is
+.B \-decodetypes
+.IR text ;
+it can be overridden, e.g., with
+.B \-decodetypes
+.I text/plain
+to restrict
+.B \-decodetext
+to just text/plain parts.
+.PP
+By default, carriage return characters are preserved or inserted at
+the end of each line of text content. The
+.B \-crlflinebreaks
+switch selects this behavior and is enabled by default. The
+.B \-nocrlflinebreaks
+switch causes carriage return characters to be stripped from, and not
+inserted in, text content when it is decoded and encoded. Note that
+its use can cause the generation of MIME messages that do not conform
+with RFC 2046, §4.1.1, paragraph 1.
+.PP
+The
.B \-textcharset
switch specifies that all text/plain parts of the message(s)
should be converted to
multipart/alternative part, if present. If not, it creates a
multipart/alternative part.
.PP
+With the
+.B \-reformat
+switch, multipart/related parts are handled differently than
+multipart/alternative. If the multipart/related has only a single
+part that is not text/plain and can be converted to text/plain, a
+text/plain part is added and the type of the part is changed to
+multipart/alternative. If the multipart/related has more than one
+part but does not have a text/plain part,
+.B mhfixmsg
+tries to add one.
+.PP
The
.B \-replacetextplain
switch broadens the applicability of
.B \-fixcte
switch enables a transformation to change the
Content-Transfer-Encoding from an invalid value to 8bit in message
-parts with a Content-Type of multipart, as required by RFC 2045,
-Section 6.4. That condition is indicated by a \*(lqmust be encoded in
-7bit, 8bit, or binary\*(rq error message from
+parts with a Content-Type of multipart and message, as required by
+RFC 2045, §6.4. That condition is indicated by a \*(lqmust be
+encoded in 7bit, 8bit, or binary\*(rq error message from
.B mhlist
and other
.B nmh
programs that parse MIME messages.
.PP
The
+.B \-fixtype
+switch ensures that each part of the message has the correct MIME type
+shown in its Content-Type header. It may be repeated. It is
+typically used to replace \*(lqapplication/octet-stream\*(rq with a
+more descriptive MIME type. It may not be used for multipart and
+message types.
+.PP
+.B mhfixmsg
+applies two transformations unconditionally.
+The first removes an extraneous trailing semicolon from the parameter
+lists of MIME header field values.
+The second replaces RFC 2047 encoding with RFC 2231 encoding of name
+and filename parameters in Content-Type and Content-Disposition header
+field values, respectively.
+.PP
+The
.B \-verbose
switch directs
.B mhfixmsg
to output informational message for each transformation applied.
+.PP
The return status of
.B mhfixmsg
is 0 if all of the requested transformations are performed, or
non-zero otherwise.
.RB ( mhfixmsg
-will not decode to binary content, but a request to do so is
-not considered a failure, and is noted with
+will not decode to binary content with the default
+.B \-decodetext
+setting, but a request to do so is not considered a failure, and is noted
+with
.BR \-verbose .)
+If a problem is detected with any one of multiple messages such that
+the return status is non-zero, then none of the messages will be
+modified.
.PP
The
.B \-file
.PP
.RS 5
.nf
-.ta \w'\-fixboundary 'u
-\-decodetext base64 and quoted-printable encoded text parts
-\-textcharset text/plain parts
-\-reformat text parts that are not text/plain
-\-fixboundary outermost multipart part
-\-fixcte multipart part
+.ta \w'\-crlflinebreaks 'u
+\-decodetext base64 and quoted-printable encoded text parts
+\-decodetypes limits parts to which -decodetext applies
+\-crlflinebreaks text parts
+\-textcharset text/plain parts
+\-reformat text parts that are not text/plain
+\-fixboundary outermost multipart part
+\-fixcte multipart or message part
+\-fixtype all except multipart and message parts
.fi
.RE
-.PP
.SS "Backup of Original Message/File"
If it applies any transformations to a message or file,
and the
profile component and negates all prior
.B \-rmmproc
switches.
-.PP
.SS "Integration with inc"
.B mhfixmsg
can be used as an add-hook, as described in %docdir%/README-HOOKS.
sets with the newly incorporated messages. Those could then be
supplied to
.BR mhfixmsg .
+An example is shown below.
.SS "Integration with procmail"
By way of example, here is an excerpt from a procmailrc file
that filters messages through
.nf
.ta \w'\-fixboundary 'u
PATH = %bindir%:$PATH
+LANG = en_US.utf8
MAILDIR = `mhparam path`
#### The Backups directory is relative to MAILDIR.
MKSTEMP = 'mkstemp -directory Backups -prefix mhfixmsg'
| tee `$MKSTEMP` | $MHFIXMSG | $STORE +nmh-workers
.fi
.RE
+.SH "EXAMPLES"
.PP
+.SS Basic usage
+To run
+.B mhfixmsg
+on the current message in the current folder, with default transformations to
+fix MIME boundaries and Content-Transfer-Encoding, to decode text and
+application/ics content parts to 8 bit, and to add a corresponding text/plain
+part where lacking:
+.PP
+.RS
+.nf
+mhfixmsg -verbose
+.fi
+.RE
+.SS Specified folder and messages
+To run
+.B mhfixmsg
+on specified messages, without its informational output:
+.PP
+.RS
+.nf
+mhfixmsg +inbox last:4
+.fi
+.RE
+.SS View without modification
+By default,
+.B mhfixmsg
+transforms the message in place. To view the MIME structure that would result from running
+.B mhfixmsg
+on the current message, without modifying the message:
+.PP
+.RS
+.nf
+mhfixmsg -outfile - | mhlist -file -
+.fi
+.RE
+.SS Search message without modification
+To search the current message, which possibly contains base64 or quoted printable encoded text parts,
+without modifiying it, use the -outfile switch:
+.PP
+.RS
+.nf
+mhfixmsg -outfile - | grep \fIpattern\fR
+.fi
+.RE
+.PP
+-outfile can be abbreviated in usual MH fashion, e.g., to -o. The search will be
+on the entire message, not just text parts.
+.SS Translate text/plain parts to UTF-8
+To translate all text/plain parts in the current message to UTF-8, in addition
+to all of the default transformations:
+.PP
+.RS
+.nf
+mhfixmsg -textcharset utf-8
+.fi
+.RE
+.SS Fix all messages in a folder
+To run
+.B mhfixmsg
+on all of the messages in a folder, using a Bourne shell loop:
+.PP
+.RS
+.nf
+for msg in `pick +folder`; do mhfixmsg $msg; done
+.fi
+.RE
+.PP
+.B mhfixmsg
+can be run on more than one message, but on a large number of messages
+may attempt to open too many files.
+.SS Run on newly incorporated messages
+To run
+.B mhfixmsg
+on messages as they are incorporated:
+.PP
+.RS
+.nf
+inc && mhfixmsg -nochangecur unseen
+.fi
+.RE
+.PP
+This assumes that the Unseen-Sequence profile entry is set to
+.BR unseen ,
+as shown in the mh\-profile(5) man page.
.SH FILES
.B mhfixmsg
looks for mhn.defaults in multiple locations: absolute pathnames are
.RB ` +folder "' defaults to the current folder"
.RB ` msgs "' defaults to cur"
.RB ` "\-decodetext 8bit"'
+.RB ` "\-decodetypes text,application/ics"'
+.RB ` \-crlflinebreaks '
.RB ` \-notextcharset '
.RB ` \-reformat '
.RB ` \-noreplacetextplain '
.B \-file
switch or an absolute pathname is used, the context will not be
modified.
+.SH BUGS
+.B mhfixmsg
+opens files internally for decoding and character set conversion, and apparently does not
+close them expeditiously. Until that is resolved, it is recommended that
+.B mhfixmsg
+not be run on a large number of messages at once, as noted in the EXAMPLES above.
projects / nmh / blobdiff