t / t5100 / info0002on commit git-diff A...B to (usually) mean "git-diff `git-merge-base A B` B" (9919f41)
   1Author: A U Thor
   2Email: a.u.thor@example.com
   3Subject: another patch
   4Date: Fri, 9 Jun 2006 00:44:16 -0700
   5