/usr/bin/interdiff

usage: interdiff [OPTIONS] patch1 patch2
       interdiff --version|--help
OPTIONS are:
  -U N, --unified=N
                  max lines of context to carry
  -i, --ignore-case
                  Consider upper- and lower-case to be the same
  -w, --ignore-all-space
                  ignore whitespace changes in patches
  -b, --ignore-space-change
                  ignore changes in the amount of whitespace
  -B, --ignore-blank-lines
                  ignore changes whose lines are all blank
      --color[=WHEN]
                  colorize the output; WHEN can be 'never', 'always',
                    or 'auto' (default: auto, use 'never' to disable)
  -p N, --strip-match=N
                  pathname components to ignore
  -q, --quiet
                  don't add rationale text
  -d PAT, --drop-context=PAT
                  drop context on matching files
  -z, --decompress
                  decompress .gz and .bz2 files
  --interpolate   run as 'interdiff'
  --combine       run as 'combinediff'
  --flip          run as 'flipdiff'
  --no-revert-omitted
                  (interdiff) When a patch from patch1 is not in patch2,
                  don't revert it
  --in-place      (flipdiff) Write the output to the original input
                  files