Script for pruning Git branches (designed to work on MacOS 11 and newer). Works with base branch "master" or "main" and you choose whether to prune remote AND local branches, or only local branches.

.zshrc

alias git-remove-merged="git-remove-merged.sh"

git-remove-merged.sh

#!/usr/bin/env zsh

autoload colors
colors

function remove_remote_branches() {
  # Remove remote branches
  git push origin $(git branch -r --merged | grep -v '/master$' | grep -v "/$current_branch$" | sed 's/origin\//:/g' | tr -d '\n')
}

function remove_local_branches() {
  # Remove local branches
  git branch -d $(git branch --merged | grep -v 'master$' | grep -v "$current_branch$" | sed 's/origin\///g' | tr -d '\n')
}

# Script to delete remote and local merged branches
current_branch=$(git branch --no-color 2>/dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/\1/')
if [ "$current_branch" != "master" ] && [ "$current_branch" != "main" ]; then
  echo "${fg_bold[red]}WARNING${reset_color}: You are on branch ${fg_bold[default]}$current_branch${reset_color}, ${fg_bold[red]}NOT${reset_color} master or main."
  echo "No branches removed."
else
  echo "Fetching merged branches..."
  git remote prune origin
  remote_branches=$(git branch -r --merged | grep -v '/master$' | grep -v "/$current_branch$")
  local_branches=$(git branch --merged | grep -v 'master$' | grep -v "$current_branch$")
  if [ -z "$remote_branches" ] && [ -z "$local_branches" ]; then
    echo "No existing branches have been merged into ${fg_bold[default]}$current_branch${reset_color} 🎉"
  else
    if [ -n "$remote_branches" ]; then
      echo "${fg_bold[default]}Remote${reset_color} branches that can be removed:"
      echo "$remote_branches"
    fi
    if [ -n "$local_branches" ]; then
      echo "${fg_bold[default]}Local${reset_color} branches that can be removed:"
      echo "$local_branches"
    fi

    PS3='Choose which branches to remove: '
    choices=("All" "Local only" "Exit")
    select ans in "${choices[@]}"; do
      case $ans in
      "All")
        if [ -n "$remote_branches" ]; then
          remove_remote_branches
        fi
        if [ -n "$local_branches" ]; then
          remove_local_branches
        fi
        break
        ;;
      "Local only")
        if [ -n "$local_branches" ]; then
          remove_local_branches
        fi
        break
        ;;
      "Exit")
        echo "No branches removed"
        exit
        ;;
      *) echo "invalid option $REPLY" ;;
      esac
    done
  fi
fi