After seeing that the project that I’m working on had 48 branches hanging out, 40 of which were completely merged and abandoned, I threw together a quick bit of one-liner (it’s still one line even if it’s more than 80 columns, right?) to delete all of the fully merged branches.

Full disclosure; this works on my machine, which happens to be a Win7 machine with some release of Cygwin on it (which I loathe):

for k in $(git branch -a --merged) | grep -v "\->\|master" | sed s/remotes\\/origin\\///);\
do $(git branch -d $k; git push origin :$k); done

And when you’re done, make sure you alert others to git remote prune origin.

The breakdown

To elaborate on this a little bit, for each branch $k in every completely merged branch:

for k in $(git branch -a --merged)

Make sure that it isn’t pointing somewhere (like HEAD would be) and isn’t master:

 | grep -v "\->\|master"

Remove the remotes/origin/ part of the branch name:

| sed s/remotes\\/origin\\///);\

Delete the local branch (if it’s there) and push the delete to the repository:

do $(git branch -d $k; git push origin :$k); done

Inspiration taken from Graham King at http://www.darkcoding.net/software/cleaning-up-old-git-branches/