MHL(1) RISC/os Reference Manual MHL(1)
NAME
mhl - produce formatted listings of MH messages
SYNOPSIS
/usr/new/lib/mh/mhl [-bell] [-nobell] [-clear] [-noclear]
[-folder +folder] [-form formfile] [-length lines]
[-width columns] [-moreproc program] [-nomoreproc]
[files ...] [-help]
DESCRIPTION
Mhl is a formatted message listing program. It can be used
as a replacement for more (1) (the default showproc ). As
with more, each of the messages specified as arguments (or
the standard input) will be output. If more than one mes-
sage 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 envariables 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.
The default format file used by mhl is called mhl.format
(which is first searched for in the user's MH directory, and
then sought in the /usr/new/lib/mh directory), this can be
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MHL(1) RISC/os Reference Manual MHL(1)
changed by using the `-form formatfile' switch.
Finally, the `-folder +folder' switch sets the MH folder
name, which is used for the "messagename:" field described
below. The envariable $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 "mhl.format" form file contains information controlling
screen clearing, screen size, wrap-around control, tran-
sparent 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 speci-
fied by the order in the format file.
Each line of mhl.format has one of the formats:
;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 "com-
ponent:" 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, speci-
fies 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 argu-
ments. If they follow a component, they apply only to 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
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(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
formatfield string format string for this component
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 arbirtray 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" (case-insensitive) will output
the actual message name (file name) preceded by the folder
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MHL(1) RISC/os Reference Manual MHL(1)
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 is:
: -- using template mhl.format --
overflowtext="***",overflowoffset=5
leftadjust,compwidth=9
ignores=msgid,message-id,received
Date:formatfield="%<(nodate{text})%{text}%|%(pretty{text})%>"
To:
cc:
:
From:
Subject:
:
extras:nocomponent
:
body:nocomponent,overflowtext=,overflowoffset=0,noleftadjust
The variable "formatfield" specifies a format string (see
mh-format(5)). 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 (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 variable addrfield or the variable datefield,
along with the variable formatfield.
FILES
/usr/new/lib/mh/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
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MHL(1) RISC/os Reference Manual MHL(1)
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' informa-
tion to the front-end.
On hosts where MH was configured with the BERK option,
address parsing is not enabled.
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