NAME

       grog - guess options for a following groff command

SYNOPSIS

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

       grog -h
       grog --help

       grog -v
       grog --version

DESCRIPTION

       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).

OPTIONS

       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.

       --ligatures
              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.

       --warnings
              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.

DETAILS

       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 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.

EXAMPLES

       Calling
              grog meintro.me
       results in
              groff -me meintro.me
       So grog recognized that the file meintro.me is written with the -me macro package.
       On the other hand,
              grog pic.ms
       outputs
              groff -p -t -e -ms pic.ms
       Besides determining the macro package -ms, grog recognized that the file pic.ms 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
              grog meintro.me pic.ms
       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 meintro.me pic.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.

AUTHORS

       grog was originally written by James Clark.  The current Perl implementation was written by Bernd  Warken
       ⟨groff-bernd.warken-72@web.de⟩  with  contributions  from  Ralph  Corderoy,  and  is maintained by Werner
       Lemberg ⟨wl@gnu.org⟩.

SEE ALSO

       groff(1), groffer(1)