# http://stevenharman.net/git-clean-delete-already-merged-branches
# delete branch that is already merge to head
git branch --merged | grep -v "\*" | xargs -n 1 git branch -d
# delete git branch that is already merge to master
git branch --merged master | grep -v "\* master" | xargs -n 1 git branch -d
# delete git branch that is already merge to origin master
git branch --merged origin/master | grep -v "\*" | xargs -n 1 git branch -d