Thanks for your patch. I have some remarks:
1) please produce a patch from the top level of a Python checkout (cf. http://www.python.org/dev/patches/);
2) wrap lines under 80 characters;
3) bug with %-formatting: the singular message takes one arg, the plural two (optparse bug, not your patch’s bug, but the patch should fix it too);
4) “usage” has been used for decades in command line parsing, it’s fine.

I’m adding Armin to the nosy list since he’s listed in py3k/Misc/maintainers.rst