MHL(1MH) COMMAND REFERENCE MHL(1MH)
NAME
mhl - produce formatted listings of MH messages
SYNOPSIS
mhl [ -clear] [-noclear] [-folder folder] [-form formfile]
[-length length] [-width width] [-help] [ filename... ]
DESCRIPTION
Mhl is a formatted message listing program. It can be used
as a replacement for more(1) (the default message lister).
The default lister can be changed by placing a "showproc:
/bin/mhl" in your ".mh_profile". As with more(1), each of
the messages specified as arguments (or stdin) will be
output. If more than one message file is specified, the
user will be prompted prior to each one, and a <RETURN> or
<eot> will begin the output, with <RETURN> clearing the
screen (if appropriate), and <eot> suppressing the screen
clear. An <interrupt> will abort the current message ouput,
prompting for the next message (if there is one), and a
<quit> will terminate the program (without core dump).
As in all MH programs, mhl looks for a line mhl: args in the
user's profile, and thus allows tailored defaults. The
switches are:
-clear Clear screen each page
-noclear Don't clear screen each page
-folderfolder Use this "folder" name
-formformfile Name of the format file
-lengthlength Screen length
-widthwidth Screen width
-help Standard help message
All of the functions these switches perform are affected or
controlled by information elsewhere. That is, the format
file can specify "clear", in which case, the command line
switches will override. Also, the length and width can be
specified in the format file, or default to 40x80. The
folder is used in constructing a message name (see special
component "MessageName" below). If it is not specified in a
switch, it is taken from the environment variable mhfolder ,
which show, next, prev, and pickinitialize appropriately.
If the form file is not specified, it is taken from the file
mhl.format in the user's MH directory; if that file doesn't
exist, it is taken from /usr/lib/mh/mhl.format. (Same
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MHL(1MH) COMMAND REFERENCE MHL(1MH)
evaluation hierarchy as the compose form file.)
Mhl operates in two phases: 1) read and parse the format
file, and 2) process each message (file). During phase 1, an
internal description of the format is produced as a
structured list. In phase 2, this list is walked for each
message, outputting message information under the format
constraints from the format file.
The mhl.format file contains information controlling screen
clearing, screen size, wraparound control, transparent text,
component ordering, and component formatting. Also, a list
of components to ignore may be specified, and a couple of
"special" components are defined to provide added
functionality. Message output will be in the order specified
by the order in the format file.
Each line of mhl.format has one of the formats:
;comment
:cleartext
variable[,variable...]
component:[variable,...]
A line beginning with a ";" is a comment, and is ignored. A
line beginning with a ":" is clear text, and is output
exactly as is. (A line containing only a ":" produces a
blank line in the output.) A line beginning with
"component:" defines the format for the specified component,
and finally, remaining lines define the global environment.
For example, the line:
width=80,length=40,clearscreen,overflowtext=***,overflowoffset=5
defines the screen size to be 80 columns by 40 rows,
specifies that the screen should be cleared prior to each
page, that the overflow indentation is 5, and that overflow
text should be flagged with "***".
Following are all of the current variables and their
arguments. If they follow a component, they apply only to
that component, otherwise, their effect is global. Since the
whole format is parsed before any output processing, the
last global switch setting for a variable applies to the
whole message.
width=# Screen width, component width
overflowtext=t Text to use at the beginning of an
overflow line
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MHL(1MH) COMMAND REFERENCE MHL(1MH)
overflowoffset=# Positions to indent overflow lines
compwidth=# Positions to indent component text
after first line
nocomponent Don't output "component: " for this
component
uppercase Output text of this component in
all upper case
center Center component on line (works for
one-line components only)
clearscreen Clear the screen (form feed) prior
to each page
leftadjust Strip off leading spaces & tabs on
each line of text
compress Change newlines in text to spaces
Where "=#" indicates a number must be specified, and "=t"
indicates that arbitrary text up to end of line or "," is
required. The variables without arguments are ON indicators,
with the default in all cases OFF. The variables
"nocomponent", center, leftadjust and compress have no
affect globally, and clearscreen only affects the global
environment.
A line of the form:
ignores=component,...
specifies a list of components which are never output.
The component "MessageName" (case is unimportant) will
output the actual message name ( filename ) preceded by
folder: if one is specified or found in the environment.
The component "Extras" will output all of the components of
the message which were not matched by explicit components,
or included in the ignore list. If this component is not
specified, an ignore list is not needed since all non-
specified components will be ignored.
If "nocomponent" is NOT specified, then the component name
will be output as it appears in the format file.
The current default format is:
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MHL(1MH) COMMAND REFERENCE MHL(1MH)
width=80,length=40,overflowtext=***,overflowoffset=5
ignores=msgid,message-id
Date:leftadjust,offset=40
To:leftadjust
Cc:leftadjust
:
From:leftadjust
Subject:leftadjust
:
extras:leftadjust,nocomponent
:
body:nocomponent
OPTIONS
-clear Clear the screen for each page.
-folder folder Use this "folder" name.
-form formfile Name of the format file.
-help Standard help message.
-length length Set screen length.
-noclear Don't clear the screen for each
page.
-width width Set screen width.
SEE ALSO
inc(1mh), more(1), next(1mh), prev(1mh), show(1mh),
mh_profile(5mh).
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