Content-type: text/html Man page of mhl


Section: User Commands (1)
Index Return to Main Contents


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.

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 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 .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 directed to a terminal, then mhl consults the $TERM and $TERMCAP 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. 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. 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



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 Form File mhl.format

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:


widthintegerscreen width or component width
lengthintegerscreen length or component length
offsetintegerpositions to indent the component
overflowtextstringtext to use at the beginning of an
overflow line
overflowoffsetintegerpositions to indent overflow lines
compwidthinteger positions to indent component text after the first line is output
uppercaseoption output text of this component in all
upper case
nouppercaseoptiondo not use uppercase
clearscreenoption/Gclear the screen prior to each page
noclearscreenoption/Gdo not clear the screen
belloption/G ring the bell at the end of each page
nobelloption/Gdisable bell
componentstring/L name to use instead of component for this component
nocomponentoption do not output component: for this component
centeroption center component on line (works for one-line components only)
nocenteroptiondo not center
leftadjustoption strip off leading white-space on each line of text
noleftadjustoptiondo not leftadjust
compressoptionchange newlines in text to spaces
nocompressoptiondo not compress
formatfieldstringformat string for this component
addrfieldoptionfield contains addresses
datefieldoptionfield 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:


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:


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)



The Form File mhl.format

This document was created by man2html, using the manual pages.
Time: 02:42:47 GMT, October 02, 2010