GROG(1)                     General Commands Manual                    GROG(1)

       grog -- guess options for a following groff command

       grog [-C] [--run] [--warnings] [--ligatures] [ groff-option ....]  [--]
            [ filespec ....]
       grog -h | --help
       grog -v | --version

       grog reads the input (file names or standard input) and  guesses  which
       of  the groff(1) options are needed to perform the input with the groff

              The corresponding groff command is usually displayed in standard
              output.   With  the  option  --run, the generated line is output
              into standard error and the generated groff command  is  run  on
              the standard output.

       The  option  -v  or --version prints information on the version number.
       Also -h or --help prints usage  information.   Both  of  these  options
       automatically end the grog program.  Other options are thenignored, and
       no groff command line is generated.  The following 3  options  are  the
       only grog options,

       -C     this  option  means enabling the groff compatibility mode, which
              is also transfered to the generated groff command line.

              this option forces to include the arguments -P-y -PU within  the
              generated groff command line.

       --run  with  this  option, the command line is output at standard error
              and then run on the computer.

              with this option, some more  warnings  are  output  to  standard

       All  other specified short options (words starting with one minus char-
       acter -) are interpreted as groff options or option  clusters  with  or
       without  argument.  No space is allowed between options and their argu-
       ment.  Except from the -marg options, all options will  be  passed  on,
       i.e.  they are included unchanged in the command for the output without
       effecting the work of grog.

       A filespec argument can either be the name of an  existing  file  or  a
       single  minus  -  to  mean standard input.  If no filespec is specified
       standard input is read automatically.

       grog reads all filespec parameters as a whole.  It tries to guess which
       of the following groff options are required for running the input under
       groff: -e, -g, -G, -j, -J, -p, -R, -s,  -t.   -man,  -mdoc,  -mdoc-old,
       -me, -mm, -mom, and -ms.

       The  guessed  groff command including those options and the found file-
       spec parameters is put on the standard output.

       It is possible to specify arbitrary groff options on the command  line.
       These  are  passed  on  the output without change, except for the -marg

       The groff program has trouble when the wrong -marg option or several of
       these  options are specified.  In these cases, grog will print an error
       message and exit with an error code.  It is better to specify no  -marg
       option.   Because  such an option is only accepted and passed when grog
       does not find any of these options or the same option is found.

       If several different -marg options are found by grog an  error  message
       is  produced and the program is terminated with an error code.  But the
       output is written with the wrong options nevertheless.

       Remember that it is not necessary to determine a macro package.  A roff
       file  can also be written in the groff language without any macro pack-
       age.  grog will produce an output without an -marg option.

       As groff also works with pure text files  without  any  roff  requests,
       grog cannot be used to identify a file to be a roff file.

       The groffer(1) program heavily depends on a working grog.

       The  grog  source  contains  two files written in different programming
       languages: is the Perl version, while is a shell script
       using  awk(1).  During the run of make(1), it is determined whether the
       system contains a suitable version  of  perl(1).   If  so,  is
       transformed into grog; otherwise is used instead.

       * Calling


         results in

                groff -me

         So  grog  recognized that the file is written with the -me
         macro package.

       * On the other hand,



                groff -p -t -e -ms

         Besides determining the macro package -ms, grog recognized  that  the
         file  additionally needs -pte, the combination of -p for pic,
         -t for tbl, and -e for eqn.

       * If both of the former example files are combined by the command


         an error message is sent to standard error because groff cannot  work
         with two different macro packages:

                grog: error: there are several macro packages: -me -ms

         Additionally  the  corresponding  output  with  the  wrong options is
         printed to standard output:

                groff -pte -me -ms

         But the program is terminated with an error code.

       * The call of

                grog -ksS -Tdvi grnexmpl.g

         contains several groff options that are just  passed  on  the  output
         without  any  interface  to  grog.  These are the option cluster -ksS
         consisting of -k, -s, and -S; and the option -T  with  argument  dvi.
         The output is

                groff -k -s -S -Tdvi grnexmpl.g

         so  no  additional  option was added by grog.  As no option -marg was
         found by grog this file does not use a macro package.

       groff(1), groffer(1) troff(1), tbl(1), pic(1), chem(1), eqn(1),
       refer(1), grn(1), grap(1), soelim(1)
              Man-pages of section 1 can be viewed with either
                     $ man name
              for text mode or
                     $ groffer name
              for graphical mode (default is PDF mode).

       groff_me(7), groff_ms(7), groff_mm(7), groff_mom(7), groff_man(7)
              Man-pages of section 7 can be viewed with either with
                     $ man 7 name
              for text mode or
                     $ groffer 7 name
              for graphical mode (default is PDF mode).

       Copyright (C) 1989-2014 Free Software Foundation, Inc.

       This file is part of grog, which is part of groff, a free software
       project.  You can redistribute it and/or modify it under the terms of
       the GNU General Public License version 2 (GPL2) as published by the
       Free Software Foundation.

       groff is distributed in the hope that it will be useful, but WITHOUT
       ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

       The text for GPL2 is available in the internet at GNU copyleft site

       Written by James Clark.

       Maintained by Werner Lemberg <>.

       Rewritten and put under GPL by Bernd Warken <groff->.

Groff Version 1.22.3           10 February 2018                        GROG(1)
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