$ diff -u /tmp/a /tmp/b
  --- /tmp/a	2015-03-24 08:33:00.021919797 -0400
  +++ /tmp/b	2015-03-24 08:33:05.629963015 -0400
  @@ -1,5 +1,5 @@
   #!/usr/bin/env bash
   set -e
   i=0
  -let i++
  +let i++ || true
   echo "i is $i"
  $ /tmp/a
  $ /tmp/b
  i is 1
  $