GROG(1)                      General Commands Manual                     GROG(1)

       grog - guess options for a following groff command

       grog [-C] [-T device] [--run] [--warnings] [--ligatures] [groff-option
            ...] [--] [filespec ...]

       grog -h
       grog --help

       grog -v
       grog --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.  A suitable device is now always written as -Tdevice including
       the groff default as -T ps.

       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.
       groffer(1) relies on a perfectly running groff(1).

       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 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, -p, -R, -s, -t (preprocessors); and -man, -mdoc,
       -mdoc-old, -me, -mm, -mom, and -ms (macro packages).

       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

       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.

       results in
              groff -me
       So grog recognized that the file is written with the -me macro
       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.

       grog was originally written by James Clark.  The current Perl
       implementation was written by Bernd Warken ⟨⟩
       with contributions from Ralph Corderoy, and is maintained by Werner
       Lemberg ⟨⟩.

       groff(1), groffer(1)

groff 1.22.4                      21 June 2021                           GROG(1)