git-rm-merged

#!/usr/bin/env bash
#
# Removes branches that have already been merged into master.
#
# See https://stackoverflow.com/a/6127884
#
upstream="origin" || "$1"
flag="-d"

# If a remote is passed, remove remote branches.
if [[ -n "${1+set}" ]]; then
	flag="-D"
fi
git checkout master
git branch --merged | egrep -v "(^\*|master|staging|develop)" | xargs git branch "${flag}"
git remote prune "$upstream"