Git alias to prune branches

git-prune-branches.sh

# Clean up branches which no longer exist on the remote
#
# @tip: Add to bash/zsh aliases
# @note: split over multiple lines to make it easier to read. 
# @see: https://gist.github.com/tgallacher/cae12db973a235b52e9e5b014d21d633
git fetch && \
 git remote prune origin && \
 git branch -v | \
 grep gone | \
 awk '{print $1;}' | \
 xargs -n 1 git branch -d