INTERDIFF(1)                       Man pages                      INTERDIFF(1)

       interdiff - show differences between two diff files

       interdiff [[-p n] | [--strip-match=n]] [[-U n] | [--unified=n]]
                 [[-d PAT] | [--drop-context=PAT]] [[-q] | [--quiet]] [[-z] |
                 [--decompress]] [[-b] | [--ignore-space-change]] [[-B] |
                 [--ignore-blank-lines]] [[-i] | [--ignore-case]] [[-w] |
                 [--ignore-all-space]] [[--interpolate] | [--combine] |
                 [--flip]] [--no-revert-omitted] diff1 diff2

       interdiff {[--help] | [--version]}

       interdiff creates a unified format diff that expresses the difference
       between two diffs. The diffs must both be relative to the same files.
       For best results, the diffs must have at least three lines of context.

       To reverse a patch, use /dev/null for diff2.

       To reduce the amount of context in a patch, use:

           interdiff -U1 /dev/null patchfile

       Since interdiff doesn't have the advantage of being able to look at the
       files that are to be modified, it has stricter requirements on the
       input format than patch(1) does. The output of GNU diff will be okay,
       even with extensions, but if you intend to use a hand-edited patch it
       might be wise to clean up the offsets and counts using recountdiff(1)

       Note, however, that the two patches must both be relative to the
       versions of the same original set of files.

       The diffs may be in context format. The output, however, will be in
       unified format.

           Ignored, for compatibility with older versions of interdiff. This
           option will go away soon.

       -p n, --strip-match=n
           When comparing filenames, ignore the first n pathname components
           from both patches. (This is similar to the -p option to GNU

       -q, --quiet
           Quieter output. Don't emit rationale lines at the beginning of each

       -U n, --unified=n
           Attempt to display n lines of context (requires at least n lines of
           context in both input files). (This is similar to the -U option to
           GNU diff(1).)

       -d PATTERN, --drop-context=PATTERN
           Don't display any context on files that match the shell wildcard
           PATTERN. This option can be given multiple times.

           Note that the interpretation of the shell wildcard pattern does not
           count slash characters or periods as special (in other words, no
           flags are given to fnmatch). This is so that "*/basename"-type
           patterns can be given without limiting the number of pathname

       -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.

       -z, --decompress
           Decompress files with extensions .gz and .bz2.

           Run as "interdiff". This is the default.

           Run as "combinediff". See combinediff(1) for more information about
           how the behaviour is altered in this mode.

           (For interpolation mode only) When a file is changed by the first
           patch but not by the second, don't revert that change.

           Display a short usage message.

           Display the version number of interdiff.

       Basic usage:

           interdiff -z 3.2pre1.patch.gz 3.2pre2.patch.gz

       Reversing a patch:

           interdiff patch /dev/null

       Reversing part of a patch (and ignoring the rest):

           filterdiff -i file.c patchfile | \
             interdiff /dev/stdin /dev/null

       There are currently no known bugs in interdiff; but there are some
       caveats. If you find a bug, please report it (along with a minimal test
       case) to Tim Waugh <>.

       There are some sets of patches in which there is just not enough
       information to produce a proper interdiff. In this case, the strategy
       employed is to revert the original patch and apply the new patch. This,
       unfortunately, means that interdiffs are not guaranteed to be


       Tim Waugh <>
           Package maintainer

       Michael K. Johnson <>
           Original man page contributor

patchutils                       23 June 2009                     INTERDIFF(1)
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