cmd:diff 

diff -UbBwd
-b     Ignore changes in amount of white space.
-B     Ignore changes that just insert or delete blank lines.
-d     Change the algorithm to perhaps find a smaller set of changes.
       This makes diff slower (sometimes much slower).
-U     Use the unified output format.
-w     Ignore white space when comparing lines.

documented on: 2007-09-22