mhl(1)mhl(1)NAMEmhl - produce formatted listings of MH messages (only available within
the message handling system, mh)
SYNOPSISmhl [options] [files...]
OPTIONS
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 out‐
putting to a terminal, then mhl causes the moreproc to be placed
between the terminal and mhl, and the switches are ignored.
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 -noclear.
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 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 directed
to a terminal, then mhl consults the $TERM and $TERMCAP environ‐
ment 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 exam‐
ple, it is directed to a pipe or a file), then mhl sends a form‐
feed after each message. 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 environ‐
mental variable $mhfolder. 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 system default file /usr/lib/mh/mhl.format. Prints
a list of the valid options to this command. Sets the screen
length. This defaults to the value indicated by $TERMINFO, if
appropriate; otherwise, it defaults to 40. Sets the screen
width. This defaults to the value indicated by $TERMINFO, if
appropriate; otherwise, it defaults to 80. 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
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 out‐
put. <RETURN> clears the screen (if appropriate), and <EOT>, usually
<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 message
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
ordering, 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 component: defines the format for the
specified component. Remaining lines define the global environment.
Examples of these are given below, together 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:
────────────────────────────────────────────────────────────────
Variable Type Semantics
────────────────────────────────────────────────────────────────
width integer screen width or component width
length integer screen length or component length
offset integer positions to indent the 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 option output text of this component in
all
upper case
nouppercase option do not use uppercase
clearscreen option/G clear the screen prior to each page
noclearscreen option/G do not clear the screen
bell option/G ring the bell at the end of each
page
nobell option/G disable bell
component string/L name to use instead of component
for this component
nocomponent option do not output component: for this
component
center option center component on line (works for
one-line components only)
nocenter option do not center
leftadjust option strip off leading white-space on
each line of text
noleftadjust option do not leftadjust
compress option change newlines in text to spaces
nocompress option do not compress
formatfield string format string for this component
addrfield option field contains addresses
datefield option 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 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 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 option
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
addrfield or the variable datefield, along with the variable format‐
field.
PROFILE COMPONENTS
Path: To determine your Mail directory
moreproc: Program to use as interactive front-end
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, speci‐
fies that the screen should be cleared prior to each page. The next
element, overflowoffset=5, states that the overflow indentation is 5.
The final element, overflowtext="***", specifies that overflow text
should be optionged with three asterisks.
The system default form file, /usr/lib/mh/mhl.format, is:
: -- using template mhl.format - - overflowtext="***",overflowoffset=5
leftadjust,compwidth=9 ignores=msid,msgid,message-id,received Date:for‐
matfield="%<(nodate{text})%{text}%|%(pretty{text})%>" To: cc: : From:
Subject: : extras:nocomponent : body:nocomponent,overflowtext=,over‐
flowoffset=0,noleftadjust
FILES
The system default form file, used to format message. The user-sup‐
plied alternate to the system default form file. The user profile.
SEE ALSOmore(1), show(1), mh_profile(4), ap(8), dp(8)mhl(1)