mark differences between groff/nroff/troff files
gdiffmk [ -a addmark ] [ -c changemark ] [ -d deletemark ] [-D [-B] [-M mark1 mark2]] [ -x diffcmd ] [ -- ] file1 file2 [output] gdiffmk --help gdiffmk --version
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.
Use the addmark for source lines not in file1 but present in file2. Default: +.
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.
Use the changemark for changed source lines. Default: |.
Use the deletemark for deleted source lines. Default: *.
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.
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 -.
Print a usage message on standard error output and exit.
Print version information on the standard output and exit.
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.
gdiffmk was written and is maintained by Mike Bianchi.