-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

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 clusterswith or without argument. No space is allowed between options and their argument. Except from the -marg options, all options willbe 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 speci‐fied standard input is read automatically.DETAILSgrog reads all filespec parameters as a whole. It tries to guess which of the following groff options are required for running theinput 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

The groff program has trouble when the wrong -marg option or several of these options are specified. In these cases, grog will printan error message and exit with an error code. It is better to specify no -marg option. Because such an option is only accepted andpassed 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 anymacro 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: grog.pl is the Perl version, while grog.sh is a shellscript using awk(1). During the run of make(1), it is determined whether the system contains a suitable version of perl(1). If so,grog.pl is transformed into grog; otherwise grog.sh is used instead.EXAMPLES* Callinggrog meintro.meresults ingroff -me meintro.meSo grog recognized that the file meintro.me is written with the -me macro package.* On the other hand,grog pic.msoutputsgroff -p -t -e -ms pic.msBesides determining the macro package -ms, grog recognized that the file pic.ms additionally needs -pte, the combination of -p forpic, -t for tbl, and -e for eqn.* If both of the former example files are combined by the commandgrog meintro.me pic.msan error message is sent to standard error because groff cannot work with two different macro packages:grog: error: there are several macro packages: -me -msAdditionally the corresponding output with the wrong options is printed to standard output:groff -pte -me -ms meintro.me pic.msBut the program is terminated with an error code.* The call ofgrog -ksS -Tdvi grnexmpl.gcontains several groff options that are just passed on the output without any interface to grog. These are the option cluster -ksSconsisting of -k, -s, and -S; and the option -T with argument dvi. The output isgroff -k -s -S -Tdvi grnexmpl.gso no additional option was added by grog. As no option -marg was found by grog this file does not use a macro package.