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 program.

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,


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.


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 error.

All other specified short options (words starting with one minus character -) are interpreted as groff options or option clusters with or without argument. No space is allowed between options and their argument. 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 filespec 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 options.

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 package. 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.


See Also

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 © 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 FITNESS FOR A PARTICULAR PURPOSE.

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.

Referenced By

gperl(1), gpinyin(1), groff(1), groffer(1), roff(7), syf.1alc(1).

4 November 2014 Groff Version 1.22.3