git diff [--options] <commit>...<commit> [--] [<path>...]
This form is to view the changes on the branch containing and up to
the second <commit>, starting at a common ancestor of both
<commit>. "git diff A...B" is equivalent to "git diff
$(git-merge-base A B) B". You can omit any one of <commit>, which
has the same effect as using HEAD instead.
git log A..B # Show me commits only on B.
git log A...B # Show me commits only on A or only on B.
git diff A..B # Show me changes only on A or only on B.
git diff A...B # Show me changes only on B.