find stale, leftover branches in git (add to ~/.gitconfig)

a.rb

stale = "! abandoned_branches() { \
        for branch in `git branch -r --no-merged | grep -v HEAD`; do \
            echo `git show --format='%ci %cr %ae' $branch | head -n 1` $branch; \
        done | sort -r | column -t; \
    }; abandoned_branches"