NAME
lexgrog - parse header information in man pages
SYNOPSIS
lexgrog
[-m|-c]
[-fhwV]
file
...
DESCRIPTION
lexgrog
is an implementation of the traditional groff guess utility in
R lex .
It reads the list of files on its command line as either man page source
files or preformatted cat pages, and displays their name and
description as used by
apropos
and
R whatis ,
the list of preprocessing filters required by the man page before it is
passed to
nroff
or
R troff ,
or both.
If its input is badly formatted,
lexgrog
will print parse failed; this may be useful for external
programs that need to check man pages for correctness.
If one of
R lexgrog 's
input files is -, it will read from standard input; if any input
file is compressed, a decompressed version will be read automatically.
OPTIONS
-m, --man
Parse input as man page source files.
This is the default if neither
--man
nor
--cat
is given.
-c, --cat
Parse input as preformatted man pages (cat pages).
--man
and
--cat
may not be given simultaneously.
-w, --whatis
Display the name and description from the man page's header, as used by
apropos
and
R whatis .
This is the default if neither
--whatis
nor
--filters
is given.
-f, --filters
Display the list of filters needed to preprocess the man page before
formatting with
nroff
or
R troff .
-h, --help
Print a help message and exit.
-V, --version
Display version information.
EXIT STATUS
0
Successful program execution.
2
lexgrog
failed to parse one or more of its input files.
EXAMPLES
$ lexgrog man.1
man.1: "man - an interface to the on-line reference manuals"
$ lexgrog -fw man.1
man.1 (t): "man - an interface to the on-line reference manuals"
$ lexgrog -c whatis.cat1
whatis.cat1: "whatis - display manual page descriptions"
$ lexgrog broken.1
broken.1: parse failed
WHATIS PARSING
mandb
(which uses the same code as
R lexgrog )
parses the
NAME
section at the top of each manual page looking for names and descriptions
of the features documented in each.
While the parser is quite tolerant, as it has to cope with a number of
different forms that have historically been used, it may sometimes fail to
extract the required information.
When using the traditional
man
macro set, a correct
NAME
section looks something like this:
.SH NAME
foo \- program to do something
Some manual pagers require the \- to be exactly as shown;
mandb
is more tolerant, but for compatibility with other systems it is
nevertheless a good idea to retain the backslash.
On the left-hand side, there may be several names, separated by commas.
The text on the right-hand side is free-form, and may be spread over
multiple lines.
If several features with different descriptions are being documented in the
same manual page, the following form is therefore used:
.SH NAME
foo, bar \- programs to do something
baz \- program to do nothing
(A macro which starts a new paragraph, like CW.PP, may be used instead
When using the BSD-derived
mdoc
macro set, a correct
NAME
section looks something like this:
.Sh NAME
.Nm foo
.Nd program to do something
There are several common reasons why whatis parsing fails.
Sometimes authors of manual pages replace .SH NAME with
.SH MYPROGRAM, and then
mandb
cannot find the section from which to extract the information it needs.
Sometimes authors include a NAME section, but place free-form text there
rather than name \- description.
However, any syntax resembling the above should be accepted.
SEE ALSO
R man (1),
R mandb (8),
R apropos (1),
R whatis (1).
NOTES
lexgrog
attempts to parse files containing .so requests, but will only be able
to do so correctly if the files are properly installed in a manual page
hierarchy.
AUTHOR
The code used by
lexgrog
to scan man pages was written by:
Wilf. (G.Wilford@ee.surrey.ac.uk).
Fabrizio Polacco (fpolacco@debian.org).
Colin Watson (cjwatson@debian.org).
Colin Watson wrote the current incarnation of the command-line
front-end, as well as this man page.
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