split the patch up into files or hunks

 Divide a patch or diff file into pieces. The split can made by file
 or by hunk basis. This makes is possible to separate changes that
 might not be desireable or assemble the patch into more coherent set
 of changes.
 .
 The hunk option opens up possibility to compare similar patches
 hunk-by-hunk using tool like interdiff(1) from patchutils package.
 Operating on hunk level also gives more control, smilar to Git, to
 selectively shelve in changes e.g. to Version Control repository.