mhn.me

早期freebsd实现

.\"	This file is automatically generated.  Do not edit!
.\" @(#)$Id: mhn.rf,v 1.14 1993/10/26 20:12:56 jromine Exp $
.SC MHN 1
.NA
mhn \- multi-media MH
.SY
mhn
\%[\%[+folder] \%[msgs] | \%[\-file\0file]]
.br
\%[\-part\0number]... \%[\-type\0content]...
.br
\%[\-list\0\%[\-headers]\0\%[\-noheaders]
.br
       \%[\-realsize]\0\%[\-norealsize]] \%[-nolist]
.br
\%[\-show\0\%[\-serialonly]\0\%[\-noserialonly]
.br
       \%[\-form\0formfile]\0\%[\-pause]\0\%[\-nopause]] \%[\-noshow]
.br
\%[\-store\0\%[\-auto]\0\%[\-noauto]] \%[\-nostore]
.br
\%[\-cache] \%[\-nocache] \%[\-rcache\0policy] \%[\-wcache\0policy]
.br
\%[\-check]\0\%[\-nocheck]
.br
\%[\-ebcdicsafe]\0\%[\-noebcdicsafe]
.br
\%[\-rfc934mode]\0\%[\-norfc934mode]
.br
\%[\-verbose]\0\%[\-noverbose]
.br
\%[\-help]
.DE
The \fImhn\fR command manipulates multi-media messages as specified in
RFC 1521.

Four action switches direct the operation of \fImhn\fR,
namely `\-list', `\-show', `\-store', and `-cache'.
Any of these switches may be used concurrently.
Normally these action switches will operate on the content of each of the
named messages.
However,
by using the `\-part' and `\-type' switches,
the scope of the operation can be focused on particular
subparts (of a multipart content) and/or particular content types.

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 `\-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 `\-part' switch will not prevent the content from being acted upon.

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 1521.
.ne 18
A list of commonly used contents is briefly reproduced here:
.sp
.nf
.in +.5i
.ta \w'application  'u
Type	Subtypes
----	--------
text	plain
multipart	mixed, alternative, digest, parallel
message	rfc822, partial, external-body
application	octet-stream, postscript
image	jpeg, gif, x-pbm, x-pgm, x-ppm, x-xwd
audio	basic
video	mpeg
.re
.in -.5i
.fi
.sp
Subtypes are mandatory.
.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 `\-type' switch,
a multipart content (of any subtype listed above) is always acted upon.
Further note that if the `\-type' switch is used,
and it is desirable to act on a message/external-body content,
then the `\-type' switch must be used twice:
once for message/external-body and once for the content externally referenced.

Each content may optionally have an integrity check associated with it.
If present and the `-check' switch is given,
then \fImhn\fR will attempt to verify the integrity of the content.

The option `\-file\ file' directs \fImhn\fR to use the specified
file as the source message, rather than a message from
a folder.
Note that the file should be a validly formatted message,
just like any other \fIMH\fR message.
It should \fBNOT\fR be in mail drop format
(to convert a file in mail drop format to a folder of \fIMH\fR messages,
see \fIinc\fR\0(1)).

.Uh "Listing the Contents"
The `\-list' switch tells \fImhn\fR to list the table of contents
associated with the named messages.
The `\-headers' switch indicates that a one-line banner should be
displayed above the listing.
The `\-realsize' switch tells \fImhn\fR 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.

.Uh "Showing the Contents"
The `\-show' switch tells \fImhn\fR to display the contents of the named
messages.
The headers of the message are displayed with the \fImhlproc\fR,
using format file \fImhl.headers\fR.
(The choice of format file can be overridden by the `\-form\0formfile' switch.)

\fImhn\fR will look for information in the user's profile to determine
how the different contents should be displayed.
This is accomplished by consulting a display string,
and executing it under \fB/bin/sh\fR,
with the standard input set to the content.
.ne 16
The display string may contain these escapes:
.sp
.nf
.in +.5i
.ta \w'%F  'u
%a	additional arguments
%e	exclusive execution
%f	filename containing content
%F	%e, %f, and stdin is terminal not content
%l	display listing prior to displaying content
%p	%l, and ask for confirmation
%s	subtype
%d	content description
.re
.in -.5i
.fi
.sp
For those display strings containing the e- or F-escape,
\fImhn\fR will execute at most one of these at any given time.
Although the F-escape expands to be the filename containing the content,
the e-escape has no expansion as far as the shell is concerned.

When the p-escape prompts for confirmation,
typing INTR (usually control-C) will tell \fImhn\fR not to display
that content.
(The p-escape can be disabled by specifying `\-nopause'.)
Further,
when \fImhn\fR is display a content,
typing QUIT (usually control-\\) will tell \fImhn\fR to wrap things up
immediately.

Note that if the content being displayed is multipart,
but not one of the subtypes listed above,
then the f- and F-escapes expand to multiple filenames,
one for each subordinate content.
Further,
stdin is not redirected from the terminal to the content.

First,
\fImhn\fR will look for an entry of the form:
.sp
.in +.5i
mhn-show-<type>/<subtype>
.in -.5i
.sp
to determine the command to use to display the content.
If this isn't found,
\fImhn\fR will look for an entry of the form:
.sp
.in +.5i
mhn-show-<type>
.in -.5i
.sp
to determine the display command.
.ne 10
If this isn't found,
\fImhn\fR has two default values:
.sp
.nf
.in +.5i
mhn-show-text/plain: %pmoreproc '%F'
mhn-show-message/rfc822: %pshow -file '%F'
.in -.5i
.fi
.sp
If neither apply,
\fImhn\fR will check to see if the message has a application/octet-stream
content with parameter \*(lqtype=tar\*(rq.
If so,
\fImhn\fR will use an appropriate command.
If not,
\fImhn\fR will complain.

.ne 10
Example entries might be:
.sp
.nf
.in +.5i
mhn-show-audio/basic: raw2audio 2>/dev/null | play
mhn-show-image: xv '%f'
mhn-show-application/PostScript: lpr -Pps
.in -.5i
.fi
.sp
Note that when using the f- or F-escape,
it's a good idea to use single-quotes around the escape.
This prevents misinterpretation by the shell of any funny characters
that might be present in the filename.

Because the text content might be in a non-ASCII character set,
when \fImhn\fR encounters a \*(lqcharset\*(rq parameter for this content,
it checks to see whether the environment variable $MM_CHARSET is set
and whether the value of this environment variable is equal to the value of
the charset parameter.
If not,
then
\fImhn\fR will look for an entry of the form:
.sp
.in +.5i
mhn-charset-<charset>
.in -.5i
.sp
which should contain a command creating an environment to render the
character set.
This command string should containing a single \*(lq%s\*(rq,
which will be filled-in with the command to display the content.

An example entry might be:
.sp
.in +.5i
mhn-charset-iso-8859-1: xterm -fn '-*-*-medium-r-normal-*-*-120-*-*-c-*-iso8859-*' -e %s
.in -.5i
.sp
Note that many pagination programs strip off the high-order bit.
However,
newer releases of the \fIless\fR program have modest support for
single-octet character sets.
The source to \fIless\fR version 177,
which has such support,
is found in the MH source tree under \fBmiscellany/less-177\fR.
In order to view messages sent in the ISO 8859/1 character set using
\fIless\fR,
.ne 9
put these lines in your \&.login file:
.sp
.nf
.in +.5i
setenv LESSCHARSET latin1
setenv LESS "-f"
.in -.5i
.fi
.sp
The first line tells \fIless\fR to use 8859/1 definition for determing
whether a character is \*(lqnormal\*(rq, \*(lqcontrol\*(lq, or
\*(lqbinary\*(rq.
The second line tells \fIless\fR not to warn you if it encounters a
file that has non-ASCII characters.
Then,
simply set the \fBmoreproc\fR profile entry to \fIless\fR,
and it will get called automatically.
(To handle other single-octet character sets,
look at the \fIless\fR\0(1) manual entry for information about the
\fBLESSCHARDEF\fR environment variable.)

Finally,
\fImhn\fR will process each message serially\0--\0it won't start showing
the next message until all the commands executed to display the
current message have terminated.
In the case of a multipart content (of any subtype listed above),
the content contains advice indicating if the parts should be
displayed serially or in parallel.
Because this may cause confusion,
particularly on uni-window displays,
the `\-serialonly' switch can be given to tell \fImhn\fR to never
display parts in parallel.

.Uh "Storing the Contents"
The `\-store' switch tells \fImhn\fR to store the contents of the
named messages in \*(lqnative\*(rq (decoded) format.
Two things must be determined:
the directory to store the content,
and the filenames.
Files are written in the directory given by the \fBmhn-storage\fR
profile entry,
.ne 6
e.g.,
.sp
.in +.5i
mhn-storage: /tmp
.in -.5i
.sp
If this entry isn't present,
the current working directory is used.

\fImhn\fR will look for information in the user's profile to determine
how the different contents should be stored.
This is achieved through the use of a formatting string,
.ne 13
which may contain these escapes:
.sp
.nf
.in +.5i
.ta \w'%P  'u
%m	message number
%P	.part
%p	part
%s	subtype
.re
.in -.5i
.fi
.sp
If the content isn't part of a multipart (of any subtype listed above) content,
the p-escapes are ignored.
Note that if the formatting string starts with a \*(lq+\*(rq character,
then these escapes are ignored,
and the content is stored in the named folder.
(A formatting string consisting solely of a \*(lq+\*(rq character
indicates the current folder.)
Further,
a formatting string consisting solely of a \*(lq-\*(rq character
indicates the standard-output.

First,
\fImhn\fR will look for an entry of the form:
.sp
.in +.5i
mhn-store-<type>/<subtype>
.in -.5i
.sp
to determine the formatting string.
If this isn't found,
\fImhn\fR will look for an entry of the form:
.sp
.in +.5i
mhn-store-<type>
.in -.5i
.sp
to determine the formatting string.
If this isn't found,
\fImhn\fR will check to see if the content is application/octet-stream
with parameter \*(lqtype=tar\*(rq.
If so,
\fImhn\fR will choose an appropriate filename.
If the content is not application/octet-stream,
then \fImhn\fR will check to see if the content is a message.
If so,
\fImhn\fR will use the value \*(lq+\*(rq.
If not,
\fImhn\fR will use the value \*(lq%m%P.%s\*(rq.

Note that if the formatting string starts with a '/',
then content will be stored in the full path given
(rather than using the value of \fBmhn-storage\fR or the current working
directory.)
Similarly,
if the formatting string starts with a '|',
then \fImhn\fR will execute a command which should ultimately store
the content.
Note that before executing the command,
\fImhn\fR will change to the appropriate directory.
Also note that if the formatting string starts with a '|',
then \fImhn\fR will also honor the a-escape when processing the
formatting string.

.ne 10
Example entries might be:
.sp
.nf
.in +.5i
mhn-store-text: %m%P.txt
mhn-store-audio/basic: | raw2audio -e ulaw -s 8000 -c 1 > %m%P.au
mhn-store-application/PostScript: %m%P.ps
.in -.5i
.fi
.sp
Further,
note that when asked to store a content containing a partial message,
\fImhn\fR will try to locate all of the portions and combine them accordingly.
Thus,