INTERDIFF(1)															      INTERDIFF(1)

NAME

       interdiff - show differences between two diff files

SYNOPSIS

       interdiff [-p n] [-U n] [-d PAT] [-Bbiqwz]
		 [--interpolate | --combine] [--no-revert-omitted]
		 diff1 diff2

       interdiff {--help | --version}

DESCRIPTION

       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) first.

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

OPTIONS

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

       -p n   When comparing filenames, ignore the first n pathname components from both patches. (This  is  similar  to  the  -p  option  to  GNU
	      patch(1).)

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

       -U 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
	      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 com-
	      ponents.

       -i     Consider upper- and lower-case to be the same.

       -w     Ignore whitespace changes in patches.

       -b     Ignore changes in the amount of whitespace.

       -B     Ignore changes whose lines are all blank.

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

       --interpolate
	      Run as ``interdiff''. This is the default.

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

       --no-revert-omitted
	      (For interpolation mode only) When a file is changed by the first patch but not by the second, don't revert that change.

       --help Display a short usage message.

       --version
	      Display the version number of interdiff.

EXAMPLES

       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

BUGS

       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 <twaugh@redhat.com>.

       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
       reversible.

SEE ALSO

       combinediff(1)

AUTHOR

       Tim Waugh <twaugh@redhat.com>.
       Man page edited by Michael K. Johnson <johnsonm@redhat.com>.

patchutils							   22 July 2002 						      INTERDIFF(1)