clean branches - HollyPony/git-documentation GitHub Wiki
Commands are UNIX only, do not try this with Microsoft system
git branch --merged | egrep -v "(^\*|master|develop)"
git branch --merged | grep -v master | xargs git branch -d
git branch -r --merged remotes/origin/master | grep -v master | sed 's/origin\///' | xargs -n 1 git push --delete origin