A handy little git porcelain to automate the removal of old topic branches you've already merged to master.
$ gem install git-trimbranches
Preflight: First, it does a git fetch and git remote prune origin in the
current working directory to make sure your list of remote branches is
up-to-date.
Finding branches that can be safely removed: Then, it uses the --merged
option to git branch to find out which branches are already merged to
origin/master. It ignores branches with names including the words "master",
"staging", "production", or "stable".
Deleting the branches: Finally, it uses git push origin :branchname to
delete each of those branches from the remote. If a local copy of the branch
exists, it is also removed. The script prints the name of each deleted branch
with its SHA so you can recreate the branch if needed.