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Name | Synopsis | Description | Options | Details | Exit status | Examples | Authors | See also | COLOPHON |
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grog(1) General Commands Manual grog(1)
grog - “groff guess”—infer the groff command a document requires
grog [--run] [--ligatures] [groff-option ...] [--] [file ...]
grog -h
grog --help
grog -v
grog --version
grog reads its input and guesses which groff(1) options are
needed to render it. If no operands are given, or if file is
“-”, grog reads the standard input stream. The corresponding
groff command is normally written to the standard output stream.
With the option --run, the generated command is written to the
standard error stream and then executed.
-h and --help display a usage message, whereas -v and --version
display version information; all exit afterward.
--ligatures
includes the arguments -P-y -PU in the generated groff
command. These are supported only by the pdf output
driver.
--run writes the inferred command to the standard error stream
and then executes it.
All other specified short options (that is, arguments beginning
with a minus sign “-” followed by a letter) are interpreted as
groff options or option clusters with or without an option
argument. Such options are included in the constructed groff
command line.
grog reads all file operands in their entirety, pattern-matching
strings that are statistically likely to be characteristic of
roff(7) documents. It tries to guess which of the following
groff options are required to correctly render the input: -e, -g,
-G, -j, -p, -R, -t (preprocessors); and -man, -mdoc, -mdoc-old,
-me, -mm, -mom, and -ms (macro packages). The inferred groff
command including these options and any file parameters is
written to the standard output stream.
It is possible to specify arbitrary groff options on the command
line. These are included in the inferred command without change.
Choices of groff options include -C to enable compatibility mode
and -T to specify an output device other than the default.
groff may issue diagnostic messages when an inappropriate -m
option, or multiple conflicting ones, are specified.
Consequently, it is best to specify no -m options to grog unless
it cannot correctly infer all of the -m arguments a document
requires.
A roff document can also be written without recourse to any macro
package. In such cases, grog will infer a groff command without
an -m option.
Limitations
grog presumes that the input does not change the escape, control,
and no-break control characters.
grog does not parse roff input line continuation or control
structures (brace escape sequences and the “if”, “ie”, and “el”
requests) nor groff's “while”. Thus the input
.if \
t .NH 1
.if n .SH
Introduction
will conceal the use of the ms macros NH and SH from grog. Such
constructions are regarded by grog's implementors as
insufficiently common to cause many inference problems; further,
preprocessors are typically even stricter when matching the macro
calls they use to bracket the regions of an input file they
textually replace. pic, for example, requires PS and PE calls to
immediately follow the default control character at the beginning
of a line, with no intervening spaces or tabs.
Detection of the -s option (the soelim(1) preprocessor) is
tricky; to correctly infer its necessity would require grog to
recursively open all files given as arguments to the .so request
under the same conditions that soelim itself does so; see its man
page. Recall that soelim is only necessary if sourced files need
to be preprocessed. Therefore, as a workaround, you may want to
run the input through soelim manually, piping it to grog, and
compare the output to running grog on the input directly. If the
“soelim”ed input causes grog to infer additional preprocessor
options, then -s is likely necessary.
$ printf ".TS\nl.\nThis is my table.\n.TE\n" > 3.roff
$ printf ".so 3.roff\n" > 2.roff
$ printf ".so 2.roff\n" > 1.roff
$ grog 1.roff
groff 1.roff
$ soelim 1.roff | grog
groff -t -
In the foregoing example, we see that this procedure enabled grog
to detect tbl(1) macros, so we would add -s as well as the
detected -t option to a revised grog or groff command.
$ grog -st 1.roff
groff -st 1.roff
grog exits with error status 1 if a macro package appears to be
in use by the input document, but grog was unable to infer which
one, or 2 if there were problems handling an option or operand.
It otherwise exits with status 0. Inferring no preprocessors or
macro packages is not an error condition; a valid roff document
need not use either, and even plain text is valid input, if one
is mindful of the syntax of the control and escape characters.
Running
grog meintro.me
at the command line results in
groff -me meintro.me
because grog recognizes that the file meintro.me is written using
macros from the me package. The command
grog pic.ms
outputs
groff -t -e -p -ms pic.ms
on the other hand. Besides discerning the ms macro package, grog
recognizes that the file pic.ms additionally needs the
combination of -t for tbl, -e for eqn, and -p for pic.
The command
grog -ksS -Tdvi grnexmpl.g
contains several groff options that are passed through without
interference from grog. These are the option cluster -ksS and
the typesetter option -T with argument dvi. The output is
groff -ksS -T dvi grnexmpl.g
so no additional option was added by grog. As no -m option was
inferred 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 ⟨groff-bernd
.warken-72@web.de⟩ with contributions from Ralph Corderoy.
groff(1)
This page is part of the groff (GNU troff) project. Information
about the project can be found at
⟨http://www.gnu.org/software/groff/⟩. If you have a bug report
for this manual page, see ⟨http://www.gnu.org/software/groff/⟩.
This page was obtained from the project's upstream Git repository
⟨https://git.savannah.gnu.org/git/groff.git⟩ on 2021-08-27. (At
that time, the date of the most recent commit that was found in
the repository was 2021-08-23.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
groff 1.23.0.rc1.654-4e1db-dir1t9yAugust 2021 grog(1)
Pages that refer to this page: gperl(1), gpinyin(1), groff(1), groffer(1), roff(7)
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