Git command to clean up local branches that no longer exist on remote. PRUNE

## Delete all local (and already merged/deleted) branches not on remote.
git fetch -p && git branch -vv | grep ': gone]' | awk '{print $1}' | xargs git branch -D

# Prune any branches that no longer exist on remote from our "remotes" list.
git fetch -p

# Show sha1 and commit subject line for each head, along with relationship to upstream branch (if any).
# Print the name of the upstream branch, as well.
git branch -vv

# Filter and only show branches that have been removed on the remote.
grep ': gone]'

# Print first column only.
awk '{print $1}'

# build and execute command lines from standard input
xargs

# Delete local branch that has same name as one of the branches we isolated in previous steps.
git branch -D