GDIFFMK(1)              FreeBSD General Commands Manual             GDIFFMK(1)

NAME
       gdiffmk - mark differences between groff/nroff/troff files

SYNOPSIS
       gdiffmk [-a addmark] [-c changemark] [-d deletemark] [-D [-B] [-M mark1
               mark2]] [-x diffcmd] [--] file1 file2 [output]

       gdiffmk --help

       gdiffmk --version

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 section "Bugs" 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.

AUTHORS
       gdiffmk was written and is maintained by Mike Bianchi <MBianchi@
       Foveal.com>.

SEE ALSO
       groff(1), nroff(1), gtroff(1), diff(1)

groff 1.22.4                   17 December 2018                     GDIFFMK(1)