MHL(1mh) - man - phpMan

 


MHL(1mh)
NAME SYNOPSIS DESCRIPTION FILES PROFILE COMPONENTS SEE ALSO DEFAULTS CONTEXT BUGS
MHL(1mh)                                                                                    MHL(1mh)



NAME
       mhl - produce formatted listings of nmh messages

SYNOPSIS
       /usr/lib/mh/mhl [-help] [-version] [-bell | -nobell] [-clear | -noclear] [-folder +folder]
            [-form formfile] [-length lines] [-width columns] [-moreproc program] [-nomoreproc]
            [-fmtproc program] [-nofmtproc] [files ...]

DESCRIPTION
       mhl  is  an  nmh  command  for  filtering and/or displaying text messages.  It is the default
       method of displaying text messages for nmh (it is the default showproc).

       As with more, each of the messages specified as arguments (or the  standard  input)  will  be
       output.   If more than one message 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 ap‐
       propriate), 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 screen at the end of each page (or output a formfeed af‐
       ter  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  ig‐
       nored.  Furthermore, if the -clear switch is used and mhl's output is directed to a terminal,
       then mhl will consult the TERM and TERMCAP environment variables to determine the user's ter‐
       minal  type  in order to find out how to clear the screen.  If the -clear switch is given 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”.  mhl will first search  for  this
       file  in  the user's nmh directory, and will then search in the directory /etc/nmh.  This de‐
       fault can be changed by using the -form formatfile switch.

       Finally, the -folder +folder switch sets the nmh folder name, which is used for the “message‐
       name:”  field  described  below.  The environment variable $mhfolder is consulted for the de‐
       fault value, which next, show, 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 format file can contain information controlling screen clearing, screen size, wrap-around
       control, transparent 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 specified by the  order  in
       the format file.

       Each line of a format file has one of the following forms:

            ;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 “component:” defines the format for the specified component,

       •   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, specifies 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 arguments.  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 (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
            rtrim          flag       trim whitespace at end of text lines
            nortrim        flag       retain whitespace at end of text
                                      lines (default)
            compress       flag       change newlines in text to spaces
            nocompress     flag       don't compress
            wrap           flag       Wrap lines that exceed width (default)
            nowrap         flag       Do not perform line wrapping
            split          flag       don't combine multiple fields into
                                      a single field
            nosplit        flag       combine multiple fields into
                                      a single field
            newline        flag       print newline at end of components
                                      (this is the default)
            nonewline      flag       don't print newline at end of components
            formatfield    string     format string for this component
                                      (see below)
            decode         flag       decode text as RFC 2047 encoded
                                      header field
            addrfield      flag       field contains addresses
            datefield      flag       field contains dates
            format         flag       Run component through formatproc filter
                                      (body only)
            noformat       flag       Do not run component through
                                      formatproc filter (default)
            formatarg      string     Argument to format filter

       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  (respec‐
       tively).

       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 name if one is specified or found in the environment.  The  for‐
       mat 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 file is:

            ; mhl.format
            ;
            ; default message filter for `show'
            ;
            :
            overflowtext="***",overflowoffset=5
            leftadjust,compwidth=9
            ignores=msgid,message-id,received,content-type,content-transfer-encoding,content-id
            Date:formatfield="%<(nodate{text})%{text}%|%(pretty{text})%>"
            To:
            cc:
            From:formatfield="%(unquote(decode{text}))"
            Subject:decode
            :
            extras:nocomponent
            :
            body:nocomponent,overflowtext=,overflowoffset=0,noleftadjust

       The variable “formatfield” specifies a format string (see mh-format(5)).  The flag  variables
       “addrfield” and “datefield” (which are mutually exclusive), tell mhl to interpret the escapes
       in the format string as either addresses or dates, respectively.

       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 flag addrfield or  datefield,  along
       with the appropriate formatfield variable string.

       The “format” flag specifies that this component will be run through the filter program speci‐
       fied by the formatproc profile entry.  This filter program is expected to read data on  stan‐
       dard input and output data on standard output.  Currently the “format” flag is only supported
       for the “body” component.  The component name will be prefixed to the output after the filter
       has  been  run.  The expected use of this is to filter a message body to create more pleasing
       text to use in a reply message.  A suggested filter to use for repl(1) is as follows:

            body:component=">",overflowtext=">",overflowoffset=0,format,nowrap

       The -fmtproc and -nofmtproc switches can be used to override the formatproc profile entry.

       The formatarg option specifies a string that is used as an argument  to  the  format  filter.
       This  string is processed by mh-format(5) and all of the message components are available for
       use.  Multiple formatarg options can be used to build up multiple  arguments  to  the  format
       filter.

FILES
       /etc/nmh/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
       formatproc:          Program to use as a filter for components that
                            have the “format” flag set.

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' information to the front-end.

       The “nonewline” option interacts badly with “compress” and “split”.

       The “format” option really should work on something other than the body component.



nmh-1.7.1                                    2014-09-15                                     MHL(1mh)

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