command prompt script for current branch

Hello,

Attached is a script I quickly wrote up yesterday. Sometimes I've found I started working only to realize I was on the wrong branch. (Now that I'm accustomed to working with git, I make many small branches, so it happens.)

So I made this small script to simply write the name of the currently checked out branch, as well as information on how many commits it differs from the remote tracking branch, if any. It also appends an exclamation mark if I have uncommitted changes. I stuck it in my PS1 environment variable, so that it would be part of my command prompt.

I tried to choose git commands that would be relatively quick, since this will be run for every single command prompt. If I've chosen suboptimal ways of doing this, please let me know. There's a few too many 'grep' and 'sed' commands for my liking, so maybe there is a way to get the same information more directly instead of parsing git command output. Anyways, if it's of general interest, I'd be happy to make a patch for /contrib.

For my tiny git repos, this seems to have pretty much no negative impact on my work flow. When I cd'd to my git.git clone there was about a 1/2-second delay the first time, but subsequent command prompts incurred no visible delay. I've no idea how fast it would be for something as big as the kernel, for example.

Steve