There were some problems with the usage message clean-up patch series. I hadn't realised that subdirectory aware scripts can't source git-sh-setup. I propose that we change this and let the scripts which are subdirectory aware set a variable, SUBDIRECTORY_OK, before they source git-sh-setup.
The scripts will also set USAGE and possibly LONG_USAGE before they source git-sh-setup. If LONG_USAGE isn't set it defaults to USAGE.
If we go this way it's easy to catch --help in git-sh-setup, print the (long) usage message to stdout and exit cleanly. git-sh-setup can define a 'usage' shell function which can be called by the scripts to print the short usage string to stderr and exit non-cleanly. It will also be easy to change $0 to basename $0 or something else, if would like to do that sometime in the future.
What follows is a patch to convert a couple of the commands to this style. If it's ok with everyone to do it this way I will convert the rest of the scripts too.
[jc: thrown in to proposed updates queue for comments.]