interdiff

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 ``*/base-
              name''-type patterns can be given without limiting the number of
              pathname components.


       -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 infor-
       mation 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)