.TH MHLIST %manext1% "August 20, 2014" "%nmhversion%"
.\"
.\" %nmhwarning%
.\"
.SH NAME
mhlist \- list information about MIME messages
.SH SYNOPSIS
.HP 5
.na
.B mhlist
.RI [ +folder ]
.RI [ msgs ]
.RB [ \-file
.IR file ]
.RB [ \-part
.IR number ]
\&...
.RB [ \-type
.IR content ]
\&...
.RB [ \-prefer
.IR content ]
\&...
.RB [ \-headers " | " \-noheaders ]
.RB [ \-realsize " | " \-norealsize ]
.RB [ \-rcache
.IR policy ]
.RB [ \-wcache
.IR policy ]
.RB [ \-check " | " \-nocheck ]
.RB [ \-changecur " | " \-nochangecur ]
.RB [ \-verbose " | " \-noverbose ]
.RB [ \-disposition " | " \-nodisposition ]
.RB [ \-version ]
.RB [ \-help ]
.ad
.SH DESCRIPTION
The
.B mhlist
command allows you to list information (essentially
a table of contents) about the various parts of a collection of
MIME (multi-media) messages.
.PP
.B mhlist
manipulates MIME (multi-media messages) as specified
in RFC 2045 to RFC 2049 (See
.IR mhbuild (1)).
.PP
The
.B \-headers
switch indicates that a one-line banner should be
displayed above the listing.
.PP
The
.B \-realsize
switch tells
.B mhlist
to evaluate the
\*(lqnative\*(rq (decoded) format of each content prior to listing.
This provides an accurate count at the expense of a small delay.
In either case, sizes will be expressed using SI prefix abbreviations
(K/M/G/T), which are based on factors of 1000.
.PP
If the
.B \-verbose
switch is present, then the listing will show
any \*(lqextra\*(rq information that is present in the message,
such as comments in the \*(lqContent-Type\*(rq header.
.PP
If the
.B \-disposition
switch is present, then the listing will show any relevant information from
the \*(lqContent-Disposition\*(rq header.
.PP
The option
.B \-file
.I file
directs
.B mhlist
to use the specified
file as the source message, rather than a message from a folder.
If you specify this file as \*(lq-\*(rq, then
.B mhlist
will
accept the source message on the standard input.  Note that the
file, or input from standard input should be a validly formatted
message, just like any other
.B nmh
message.  It should
.B NOT
be in mail drop format (to convert a file in mail drop format to
a folder of
.B nmh
messages, see
.IR inc (1)).
.PP
By default,
.B mhlist
will list information about the entire
message (all of its parts).  By using the
.B \-part
and
.B \-type
switches, you may limit the scope of this command to particular
subparts (of a multipart content) and/or particular content types.
.PP
A part specification consists of a series of numbers separated by dots.
For example, in a multipart content containing three parts, these
would be named as 1, 2, and 3, respectively.  If part 2 was also a
multipart content containing two parts, these would be named as 2.1 and
2.2, respectively.  Note that the
.B \-part
switch is effective for only
messages containing a multipart content.  If a message has some other
kind of content, or if the part is itself another multipart content, the
.B \-part
switch will not prevent the content from being acted upon.
.PP
A content specification consists of a content type and a subtype.
The initial list of \*(lqstandard\*(rq content types and subtypes can
be found in RFC 2046.
.PP
A list of commonly used contents is briefly reproduced here:
.PP
.RS 5
.nf
.ta \w'application  'u
Type	Subtypes
----	--------
text	plain, enriched
multipart	mixed, alternative, digest, parallel
message	rfc822, partial, external-body
application	octet-stream, postscript
image	jpeg, gif, png
audio	basic
video	mpeg
.fi
.RE
.PP
A legal MIME message must contain a subtype specification.
.PP
To specify a content, regardless of its subtype, just use the
name of the content, e.g., \*(lqaudio\*(rq.  To specify a specific
subtype, separate the two with a slash, e.g., \*(lqaudio/basic\*(rq.
Note that regardless of the values given to the
.B \-type
switch, a
multipart content (of any subtype listed above) is always acted upon.
Further note that if the
.B \-type
switch is used, and it is desirable to
act on a message/external-body content, then the
.B \-type
switch must
be used twice: once for message/external-body and once for the content
externally referenced.
.PP
By default, the parts of a multipart/alternative part are listed in
the reverse order of their placement in the message.  The listing
therefore is in decreasing order of preference, as defined in RFC
2046.  The
.B \-prefer
switch can be used (one or more times, in order of descending
preference) to let MH know which content types from a
multipart/alternative MIME part are preferred by the user, in order to
override the default preference order.  Thus, when viewed by
.BR mhlist ,
the ordering of multipart/alternative parts will appear to change when
invoked with or without various
.B \-prefer
switches.
The
.B \-prefer
switch is functionally most important for
.IR mhshow ,
but is also implemented in
.B mhlist
and
.B mhstore
to make common part number ordering possible across all three programs.
.SS "Checking the Contents"
The
.B \-check
switch tells
.B mhlist
to check each content for an
integrity checksum.  If a content has such a checksum (specified as a
Content-MD5 header field), then
.B mhlist
will attempt to verify the
integrity of the content.
.SH FILES
.fc ^ ~
.nf
.ta \w'%nmhetcdir%/ExtraBigFileName  'u
^$HOME/\&.mh\(ruprofile~^The user profile
.fi
.SH "PROFILE COMPONENTS"
.fc ^ ~
.nf
.ta 2.4i
.ta \w'ExtraBigProfileName  'u
^Path:~^To determine the user's nmh directory
^Current\-Folder:~^To find the default current folder
.fi
.SH "SEE ALSO"
.IR mhbuild (1),
.IR mhshow (1),
.IR mhstore (1)
.SH DEFAULTS
.nf
.RB ` +folder "' defaults to the current folder"
.RB ` msgs "' defaults to cur"
.RB ` \-nocheck '
.RB ` \-headers '
.RB ` \-realsize '
.RB ` \-rcache\ ask '
.RB ` \-wcache\ ask '
.RB ` \-changecur '
.RB ` \-noverbose '
.RB ` \-nodisposition '
.fi
.SH CONTEXT
If a folder is given, it will become the current folder.  The last
message selected will become the current message, unless the
.B \-nochangecur
option is specified.