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mhl - produce formatted listings of MH messages (only available within the message handling system, mh)
mhl [options] [files...]
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.
The defaults for this command are:
-bell -noclear -length 40 -width 80
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 standard 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>, 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 mhl.format form file contains information controlling screen clearing, 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 specified 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 environment. 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 containing 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
formatfield.
Path: To determine your Mail directory
moreproc: Program to use as interactive front-end
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 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:formatfield="%<(nodate{text})%{text}%|%(pretty{text})%>" To: cc: : From: Subject: : extras:nocomponent : body:nocomponent,overflowtext=,overflowoffset=0,noleftadjust
The system default form file, used to format message.
The user-supplied alternate to the system default form file.
The user profile.
more(1), show(1), mh_profile(4), ap(8), dp(8)