These utilities are made for manipulating unified context diffs.  The unified
diff is a fairly recent critter that combines the old and new hunks of a
context diff into one hunk.  This is smaller than a normal context diff by
about 20% (I've seen from 12% to 48%, depending on the number of redundant
context lines that are no longer needed).

Keep in mind that _no_information_is_lost_ by the conversion of a context
diff into a unified diff.  Only the redundant context lines that present
the same information twice.

If you're worried that some people will be unable to apply a patch released
as a unified diff then you could distribute the "unipatch.c" program -- 1.5k
of C source that converts a unified diff into a context diff that any version
of patch can understand.

The main utility is in unify.c, which is capable of transforming a context
diff into a unified diff and back again.  It is also able to do useful
filtering of the patch as it is converted.  For example, I use unify with
the -U option to transform raw diff output into a releasable patch.  See
the man page for details.

If you find that you like unified diffs, you may like to know that gnu diff
version 1.15 creates them directly with the -u (+unified) option, and patch
version 12u4 can apply them.  You can grab both of these from any gnu archive
site.

Version 1.1 of the utilities properly handles the abbreviated header line
introduced in gnu diff 1.15.  It also adds the -= and -o options to unify.

 \  /| / /|\/ /| /(_)     Wayne Davison
(_)/ |/ /\|/ / |/  \      davison@borland.com
   (W   A  Y   N   e)