git-branch-prune-local

#!/bin/bash
{
set -euo pipefail
function show_help() {
    cat <<HELP
Usage:      git-branch-prune-local  [ -h ]

    Delete local branches where the upstream branch is gone.

Options:

    -h      Print this help text and exit.

HELP
}

if (( $# == 1 )) && [[ "$1" == "-h" ]]
then
    show_help
    exit 0
fi
if (( $# != 0 ))
then
    echo 1>&2 "Error: Invalid option. Try '-h'."
    exit 1
fi
if [ -n "$(git status --porcelain)" ]
then
    echo ">>> Error: Please commit changes first." 1>&2
    exit 1
fi

current_branch="$(git symbolic-ref -q HEAD)"
current_branch="${current_branch##refs/heads/}"
current_branch="${current_branch:-HEAD}"

function clean_up() {
    if [ "$current_branch" != "HEAD" ] && git show-ref --quiet refs/heads/"$current_branch"
    then
        git checkout "$current_branch" &>/dev/null
    fi
}
trap clean_up EXIT

branch=master
if ! git show-ref --quiet refs/heads/$branch
then
    branch=main
    if ! git show-ref --quiet refs/heads/$branch
    then
        echo ">>> Error: Can't switch to main or master?" 1>&2
        exit 1
    fi
fi
git checkout "$branch" &>/dev/null

IFS=$'\n'
# git remote prune origin # Only useful if origin is different than the 'fetch' below:
git fetch --prune --prune-tags --force

script_path="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
askyn="$script_path/askYN"

branches="$( git branch -vv | grep ': gone]' | awk '{print $1}' )"

for branch in $branches
do
    if $askyn "Delete ${branch}?"
    then
        git branch -D "$branch"
    fi
done

exit 0
}