Show what branch you are working on in a command prompt

Since I have to juggle between several projects on my typical day job, it would be nice if I can see which branch I am on in a git repository. I figured it out just a single line in my .bashrc:

local GIT='$(git branch &>/dev/null; if [ $? -eq 0 ]; then echo "($(git branch | grep '^*' |sed s/\*\ //))"; fi)'

Then add it to your prompt:

PS1="\u$....${GIT}${NONE}\$ "

Now I get:
~/Projects/spice-workspace/spice2(master)$ git checkout develop
~/Projects/spice-workspace/spice2(develop)$

Very cool!

Git

I was having a problem with my git add -i command, here is the error message:

Can't locate Error.pm in @INC (@INC contains: /opt/local/lib/perl5/site_perl/5.8.8 /System/Lib....

After playing with it for a while, I finally find that when I use mac port to install the git-core, it failed to copy the Error.pm file to the working directory. Here is how to fix it:

$sudo cp /opt/local/lib/perl5/vendor_perl/5.8.8/Error.pm /opt/local/lib/perl5/site_perl/5.8.8/.

I am hoping this could save someone sometime to find the answer.