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LEXGROG(1)		      Manual pager utils		    LEXGROG(1)

       lexgrog - parse header information in man pages

       lexgrog [-m|-c] [-fhwV] file ...

       lexgrog	is  an implementation of the traditional groff guess utility
       in 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 whatis, the list of  preprocess
       ing  filters  required  by the man page before it is passed to nroff or
       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 lexgrogs input files is -, it will  read
       from  standard  input;  if any input file is compressed, a decompressed
       version will be read automatically.

       -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 pages header,  as
	      used  by	apropos  and  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 troff.

       -h, --help
	      Print a help message and exit.

       -V, --version
	      Display version information.

       0      Successful program execution.

       1      Usage error.

       2      lexgrog failed to parse one or more of its input files.

	 $ 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

       mandb  (which uses the same code as 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 neverthe
       less 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 there
       fore used:

	      .SH NAME
	      foo, bar \- programs to do something
	      baz \- program to do nothing

       (A macro which starts a new paragraph, like .PP, may be used instead of
       the break macro .br.)

       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  informa
       tion  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.

       man(1), mandb(8), apropos(1), whatis(1).

       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.

       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.

2.4.3				  2005-07-03			    LEXGROG(1)

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