man > gdiffmk(1)

gdiffmk(1)                             General Commands Manual                            gdiffmk(1)

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

Synopsis
       gdiffmk [-a add-mark] [-c change-mark] [-d delete-mark] [-x diff-command] [-D [-B] [-M mark1
               mark2]] [--] file1 file2 [output]

       gdiffmk --help

       gdiffmk --version

Description
       gdiffmk compares two roff(7) documents, file1 and file2, and creates a roff document consist‐
       ing  of  file2 with added margin character (.mc) requests indicating output lines that differ
       from file1.  If the file1 or file2 argument is “-”, gdiffmk reads the standard  input  stream
       for  that  input.   If the output operand is present, gdiffmk writes output to a file of that
       name.  If it is “-” or absent, gdiffmk writes output to the standard output stream.  “-” can‐
       not be both an input and output operand.

Options
       --help displays a usage message and --version shows version information; both exit afterward.

       -a add-mark
              Use add-mark 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 roff break re‐
              quest, .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  pro‐
              gram not to insert these breaks; it makes no sense to use it without -D.

       -c change-mark
              Use change-mark for changed source lines.  Default: “|”.

       -d delete-mark
              Use the delete-mark for deleted source lines.  Default: “*”.

       -D     Show the deleted portions from changed and deleted text.

       -M mark1 mark2
              Change  the  delimiting marks for the -D option.  It makes no sense to use this option
              without -D.  Default delimiting marks: “[[” ... “]]”.

       -x diff-command
              Use the diff-command command to perform the comparison of file1 and file2.  In partic‐
              ular, diff-command should accept the GNU diff(1) -D option.  Default: diff.

       --     Treat all subsequent arguments as file names, even if they begin with “-”.

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

       gdiffmk relies on the -D option of GNU diff to make a merged “#ifdef” output format.  Busybox
       diff is known to not support it.  Also see the -x diff-command option.

Authors
       gdiffmk was written by Mike Bianchi, now retired.  It is maintained by the groff developers.

See also
       groff(1), nroff(1), gtroff(1), roff(7), diff(1)

groff 1.23.0                                31 March 2024                                 gdiffmk(1)