NAME

SYNOPSIS

       gdiffmk [ -aaddmark ] [ -cchangemark ] [ -ddeletemark ] [ -D [ -B ] [ -Mmark1 mark2 ] ] [ -xdiffcmd ]
               [ -- ] [ --help ] [ --version ] file1 file2 [ output ]

DESCRIPTION

       gdiffmk  compares  two  groff(1), nroff(1), or troff(1) documents, file1 and file2, and creates an output
       which is file2 with added `margin character' (.mc) commands that indicate the differences.

       If the output filename is present, the output is written there.  If it is  -  or  absent  the  output  is
       written to the standard output.

       If the file1 or file2 argument is - the standard input is read for that input.  Clearly both cannot be -.

       Note  that  the  output is not necessarily compatible with all macro packages and all preprocessors.  See
       the BUGS section below.

OPTIONS

       -aaddmark
              Use the addmark for source lines not in file1 but present in file2.  Default: +.

       -B     By default, the deleted texts marked by the -D option end with an added troff break command,  .br,
              to  ensure  that  the  deletions  are  marked  properly.   This  is the only way to guarantee that
              deletions and small changes get flagged.  This option directs the  program  not  to  insert  these
              breaks; it makes no sense to use it without -D.

       -cchangemark
              Use the changemark for changed source lines.  Default: |.

       -ddeletemark
              Use the deletemark for deleted source lines.  Default: *.

       -D     Show the deleted portions from changed and deleted text.  Default delimiting marks: [[ ... ]].

       -Mmark1 mark2
              Change the delimiting marks for the -D option.  It makes no sense to use this option without -D.

       -xdiffcmd
              Use  the  diffcmd  command  to  perform the comparison of file1 and file2.  In particular, diffcmd
              should accept the GNU diff -Dname option.  Default: diff(1).

       --     All the following arguments are treated as file names, even if they begin with -.

       --help Print a usage message on standard error output and exit.

       --version
              Print version information on the standard output and exit.

BUGS

       The output is not necessarily compatible with all macro packages and  all  preprocessors.   A  workaround
       that  is  often  successful  against  preprocessor  problems  is  to run gdiffmk on the output of all the
       preprocessors instead of the input source.

       gdiffmk relies on the -Dname option of GNU diff(1) to make a merged `#ifdef' output  format.   It  hasn't
       been tested whether other versions of diff(1) do support this option.  See also the -xdiffcmd option.

       Report  bugs to bug-groff@gnu.org.  Include a complete, self-contained example that will allow the bug to
       be reproduced, and say which version of gdiffmk you are using.

COPYRIGHT

       Copyright © 2004-2014 Free Software Foundation, Inc.

       This file is part of the gdiffmk utility, which is part of groff, a free software project.

       You can redistribute and/or modify gdiffmk under the terms of the GNU General Public License as published
       by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

       gdiffmk 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.  See the GNU General Public
       License for more details.

       You should have received a copy of the GNU General Public License along with this program.  If  not,  see
       <http://www.gnu.org/licenses/>.

AUTHORS