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
       consisting  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.  “-” cannot 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
              request,  .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.

       -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
              particular, 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 ⟨MBianchi@Foveal.com⟩, now retired.  It is  maintained
       by the groff developers.

See also

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