cdif is a post-processor of the Unix diff command.  It highlights
deleted, changed and added words based on word context.  You may want
to compare character-by-character rather than word-by-word.  Option -B
option can be used for that purpose.  If only one file is specified,
cdif reads that file (stdin if no file) as a output from diff command.
Lines those don't look like diff output are simply ignored and
printed.

Note that this requires fdescfs(5) mounted.