sdif is inspired by System V sdiff(1) command.  The basic feature of
sdif is making a side-by-side listing of two different files.  All
contents of two files are listed on left and right sides.  Center
column is used to indicate how different those lines.  No mark means
no difference.  Added, deleted and modified lines are marked with `-'
and `+' character.

It also reads and formats the output from diff command from standard
input.  Besides normal diff output, context diff -c and unified diff
-u output will be handled properly.  Combined diff format is also
supported, but currently limited upto three files.

WWW: https://github.com/kaz-utashiro/sdif