git-stale-branches

#!/usr/bin/env bash

if ! git config --get-all remote.origin.fetch | grep -q '/pr/'; then
    git config --add remote.origin.fetch '+refs/pull/*:refs/remotes/origin/pr/*'
fi

git fetch --all

for r in $(git branch -r --format='%(refname)'); do
    git branch --merged "$r";
done | sort -u | grep -v '^\*' | xargs -r echo # git branch -D