MHL(1) [nmh-1.0.4] (MH.6.8) MHL(1)
NAME
mhl - produce formatted listings of nmh messages
SYNOPSIS
/usr/freeware/lib/nmh/mhl [-bell] [-nobell] [-clear]
[-noclear] [-folder +folder] [-form formfile]
[-length lines] [-width columns] [-moreproc program]
[-nomoreproc] [files ...] [-version] [-help]
DESCRIPTION
Mhl is a nmh command for filtering and/or displaying text
messages. It is the default method of displaying text
messages for nmh (it is the default showproc).
As with more, each of the messages specified as arguments
(or the standard input) 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> (usually CTRL-D) suppressing the screen clear. An
<INTERRUPT> (usually CTRL-C) will abort the current message
output, prompting for the next message (if there is one),
and a <QUIT> (usually CTRL-\) will terminate the program
(without core dump).
The `-bell' option tells mhl to ring the terminal's bell at
the end of each page, while the `-clear' option tells mhl to
clear the scree at the end of each page (or output a
formfeed after each message). Both of these switches (and
their inverse counterparts) take effect only if the profile
entry moreproc is defined but empty, and mhl is outputting
to a terminal. If the moreproc entry is defined and non-
empty, and mhl is outputting to a terminal, then mhl will
cause the moreproc to be placed between the terminal and mhl
and the switches are ignored. Furthermore, if the `-clear'
switch is used and mhl's output is directed to a terminal,
then mhl will consult the $TERM and $TERMCAP environment
variables to determine the user's terminal type in order to
find out how to clear the screen. If the `-clear' switch is
used and mhl's output is not directed to a terminal (e.g., a
pipe or a file), then mhl will send a formfeed after each
message.
To override the default moreproc and the profile entry, use
the `-moreproc program' switch. Note that mhl will never
start a moreproc if invoked on a hardcopy terminal.
The `-length length' and `-width width' switches set the
screen length and width, respectively. These default to the
values indicated by $TERMCAP, if appropriate, otherwise they
default to 40 and 80, respectively.
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MHL(1) [nmh-1.0.4] (MH.6.8) MHL(1)
The default format file used by mhl is called mhl.format.
mhl will first search for this file in the user's nmh
directory, and will then search in the directory
/usr/freeware/lib/nmh/etc. This default can be changed by
using the `-form formatfile' switch.
Finally, the `-folder +folder' switch sets the nmh folder
name, which is used for the messagename: field described
below. The environment variable $mhfolder is consulted for
the default value, which show, next, and prev initialize
appropriately.
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 format file can contain information controlling screen
clearing, screen size, wrap-around 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 a format file has one of the following forms:
;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
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MHL(1) [nmh-1.0.4] (MH.6.8) MHL(1)
that component, otherwise, their affect 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 if that variable is used in a global context
(i.e., bell, clearscreen, width, length).
variable type semantics
width integer screen width or component width
length integer screen length or component length
offset integer positions to indent component:
overflowtext string text to use at the beginning of an
overflow line
overflowoffset integer positions to indent overflow lines
compwidth integer positions to indent component text
after the first line is output
uppercase flag output text of this component in all
upper case
nouppercase flag don't uppercase
clearscreen flag/G clear the screen prior to each page
noclearscreen flag/G don't clearscreen
bell flag/G ring the bell at the end of each page
nobell flag/G don't bell
component string/L name to use instead of component for
this component
nocomponent flag don't output component: for this
component
center flag center component on line (works for
one-line components only)
nocenter flag don't center
leftadjust flag strip off leading whitespace on each
line of text
noleftadjust flag don't leftadjust
compress flag change newlines in text to spaces
nocompress flag don't compress
split flag don't combine multiple fields into
a single field
nosplit flag combine multiple fields into
a single field
newline flag print newline at end of components
(this is the default)
nonewline flag don't print newline at end of components
formatfield string format string for this component
(see below)
decode flag decode text as RFC-2047 encoded
header field
addrfield flag field contains addresses
datefield flag field contains dates
To specify the value of integer-valued and string-valued
variables, follow their name with an equals-sign and the
value. Integer-valued variables are given decimal values,
while string-valued variables are given arbitrary text
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MHL(1) [nmh-1.0.4] (MH.6.8) MHL(1)
bracketed by double-quotes. If a value is suffixed by /G or
/L, then its value is useful in a global-only or local-only
context (respectively).
A line of the form:
ignores=component,...
specifies a list of components which are never output.
The component MessageName (case-insensitive) will output the
actual message name (file name) preceded by the folder name
if one is specified or found in the environment. The format
is identical to that produced by the `-header' option to
show.
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 default format file is:
; mhl.format
;
; default message filter for `show'
;
:
overflowtext="***",overflowoffset=5
leftadjust,compwidth=9
ignores=msgid,message-id,received,content-type,content-transfer-encoding,content-id
Date:formatfield="%<(nodate{text})%{text}%|%(pretty{text})%>"
To:
cc:
From:decode
Subject:decode
:
extras:nocomponent
:
body:nocomponent,overflowtext=,overflowoffset=0,noleftadjust
The variable formatfield specifies a format string (see
mh-format (5)). The flag variables addrfield and datefield
(which are mutually exclusive), tell mhl to interpret the
escapes in the format string as either addresses or dates,
respectively.
By default, mhl does not apply any formatting string to
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MHL(1) [nmh-1.0.4] (MH.6.8) MHL(1)
fields containing address or dates (see mh-mail (5) for a
list of these fields). Note that this results in faster
operation since mhl must parse both addresses and dates in
order to apply a format string to them. If desired, mhl can
be given a default format string for either address or date
fields (but not both). To do this, on a global line
specify: either the flag addrfield or datefield, along with
the appropriate formatfield variable string.
FILES
/usr/freeware/lib/nmh/etc/mhl.format The message template
or <mh-dir>/mhl.format Rather than the standard template
$HOME/.mh_profile The user profile
PROFILE COMPONENTS
moreproc: Program to use as interactive front-end
SEE ALSO
show(1), ap(8), dp(8)
DEFAULTS
`-bell'
`-noclear'
`-length 40'
`-width 80'
CONTEXT
None
BUGS
There should be some way to pass `bell' and `clear'
information to the front-end.
The nonewline option interacts badly with compress and
split.
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