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Command: mhl | Section: 1 | Source: Digital UNIX | File: mhl.1.gz
mhl(1) General Commands Manual mhl(1)
NAME
mhl - produce formatted listings of MH messages (only available within
the message handling system, mh)
SYNOPSIS
mhl [ options ] [ files... ]
DESCRIPTION
The mhl command is a program for listing formatted messages, which can
be used as a replacement for more, the default showproc program.
As with more, each of the messages specified as arguments (or the stan-
dard input) are output. If more than one message file is specified,
you are prompted prior to each one, and a <RETURN> or <EOT> begins the
output. <RETURN> clears the screen (if appropriate), and <EOT>, usu-
ally <CTRL/D>, suppresses the screen clear. An <INTERRUPT>, usually
<CTRL/C>, aborts the current message output, prompting for the next
message, if there is one. A <QUIT>, usually <CTRL/E>, terminates the
program without generating a core dump.
The mhl command operates in two phases: it reads and parses the format
file; then it processes each message (file). During the first phase,
an internal description of the format is produced as a structured list.
In the second phase, this list is traversed for each message, and mes-
sage information is output according to the instructions contained in
the format file.
The Form File mhl.format
The mhl.format form file contains information controlling screen clear-
ing, screen size, wrap-around control, transparent text, component or-
dering, and component formatting. A list of components that should be
ignored may also be specified, and some special components are defined
to provide added functionality. Message output is in the order speci-
fied by the order in the format file.
Each line of the mhl.format file has one of the following formats:
;comment
:cleartext
variable[variable...]
component:[variable...] A line beginning with a semi colon (;) is
a comment, and is ignored. A line beginning with a colon (:) is clear
text, and is output exactly as it is. A line containing only a colon
(:) produces a blank line in the output. A line beginning with compo-
nent: defines the format for the specified component. Remaining lines
define the global environment. Examples of these are given below, to-
gether with the system default form file.
If variables or arguments 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, provided that the variable
is used in a global context (bell, clearscreen, width, length). All of
the current variables and their arguments are shown in the following
table:
tab(+); l l l. _
Variable+Type+Semantics
_
width+integer+screen width or component width length+integer+screen
length or component length offset+integer+positions to indent the com-
ponent overflowtext+string+text to use at the beginning of an ++over-
flow 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+do not use uppercase
clearscreen+flag/G+clear the screen prior to each page no-
clearscreen+flag/G+do not clear the screen bell+flag/G+ring the bell at
the end of each page nobell+flag/G+disable bell component+string/L+name
to use instead of component for ++this component nocomponent+flag+do
not output component: for this ++component center+flag+center component
on line (works for ++one-line components only) nocenter+flag+do not
center leftadjust+flag+strip off leading white-space on each ++line of
text noleftadjust+flag+do not leftadjust compress+flag+change newlines
in text to spaces nocompress+flag+do not compress format-
field+string+format string for this component addrfield+flag+field con-
tains 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-val-
ued variables are given decimal values, while string-valued variables
are given arbitrary text bracketed by double-quotes. If a value is
suffixed by /G or /L, then its value is useful in a global-only or lo-
cal-only context (respectively). A line of the form:
ignores=component,... specifies a list of components which are
never output.
The component MessageName outputs the actual message name (file name)
preceded by the folder name if one is specified or found in the envi-
ronment. The format is identical to that produced by the -header op-
tion to show.
The component Extras outputs 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 are ignored.
If -nocomponent is not specified, then the component name is output as
it appears in the format file.
The variable formatfield specifies a format string; see mh-format(4).
The variables addrfield and datefield, which are mutually exclusive,
control the interpretation of the escapes.
By default, mhl does not apply any formatting string to fields contain-
ing address or dates; see mh-mail(4) for a list of these fields. 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 variable ad-
drfield or the variable datefield, along with the variable formatfield.
FLAGS
-bell
-nobell Tells mhl to ring the terminal bell at the end of each page.
This is the default behavior. You can suppress this by using
the -nobell option.
This option takes effect only if the profile entry moreproc
is defined but empty, and if mhl is outputting to a terminal.
If the moreproc entry is defined and non-empty, and mhl is
outputting to a terminal, then mhl causes the moreproc to be
placed between the terminal and mhl, and the switches are ig-
nored.
-clear
-noclear Tells mhl to clear the screen at the end of each page, or
output a formfeed after each message. You can suppress this
by using the -noclear option. The default behavior is -no-
clear.
This option takes effect only if the profile entry moreproc
is defined but empty, and if mhl is outputting to a terminal.
If the moreproc entry in the user's .mh_profile is defined
and non-empty, and mhl is outputting to a terminal, then mhl
causes the moreproc program to be placed between the terminal
and mhl, and the options are ignored.
If the -clear option is used and the output of mhl is di-
rected to a terminal, then mhl consults the $TERM and $TERM-
CAP environment variables to determine your terminal type in
order to find out how to clear the screen. If the -clear
switch is used and the output of mhl is not directed to a
terminal (if, for example, it is directed to a pipe or a
file), then mhl sends a formfeed after each message.
-folder +foldername
Sets the folder name. This is used by components in the
mhl.format form file to output the message name. If you do
not use this option, mhl consults the environmental variable
$mhfolder.
-form formfile
Specifies the format file used. If this option is not given,
mhl searches in your Mail directory for a file called
mhl.format; or, if this file does not exist, it uses the sys-
tem default file /usr/lib/mh/mhl.format.
-help Prints a list of the valid options to this command.
-length lines
Sets the screen length. This defaults to the value indicated
by $TERMINFO, if appropriate; otherwise, it defaults to 40.
-width columns
Sets the screen width. This defaults to the value indicated
by $TERMINFO , if appropriate; otherwise, it defaults to 80.
-moreproc program
-nomoreproc
Overrides the default moreproc program. Note that mhl never
starts a moreproc if invoked on a hardcopy terminal.
The defaults for this command are:
-bell
-noclear
-length 40
-width 80
EXAMPLES
The first example gives a typical line of a form file:
width=80,length=40,clearscreen,overflowtext="***",overflowoffset=5 The
first two elements define the screen width to be 80 characters, and the
screen length to be 40 lines. The next element, clearscreen, specifies
that the screen should be cleared prior to each page. The next ele-
ment, overflowoffset=5, states that the overflow indentation is 5. The
final element, overflowtext="***", specifies that overflow text should
be flagged with three asterisks.
The system default form file, /usr/lib/mh/mhl.format, is: : -- using
template mhl.format - - overflowtext="***",overflowoffset=5 leftad-
just,compwidth=9 ignores=msid,msgid,message-id,received Date:format-
field="%<(nodate{text})%{text}%|%(pretty{text})%>" To: cc: : From: Sub-
ject: : extras:nocomponent : body:nocomponent,overflowtext=,over-
flowoffset=0,noleftadjust
PROFILE COMPONENTS
tab(+); l l. Path:+To determine your Mail directory moreproc:+Program
to use as interactive front-end
FILES
/usr/lib/mh/mhl.format
The system default form file, used to format message.
<mh-dir>/mhl.format
The user-supplied alternate to the system default form file.
$HOME/.mh_profile
The user profile.
RELATED INFORMATION
more(1), show(1), mh_profile(4), ap(8), dp(8) delim off
mhl(1)