Bash function to clean up all locally merged branches and worktrees. Add to your .zshrc or .bashrc and run `gitcleanup` in terminal to make the magic happen

gitcleanup.sh

# gitcleanup: remove merged branches and their worktrees, after ensuring everything is up‑to‑date
# Usage: gitcleanup [target-branch]
#
# 1. Ensure the target branch exists, is clean, and up‑to‑date with origin.
# 2. For every local branch already merged into the target:
#      • If the branch has a worktree and that worktree is clean, fast‑forward it with `git pull --ff-only`.
#      • If the worktree remains clean, remove the worktree and delete the branch.
#      • If the branch has no worktree, delete the branch directly.
# 3. Stale worktree records are pruned first.

gitcleanup() {
  local target=${1:-main}            # merge base (default: main)

  # 1. Sync refs
  echo "Fetching latest refs from all remotes…"
  git fetch --prune --all || return 1

  # Remember where we were, so we can come back later
  local current_branch
  current_branch=$(git symbolic-ref --quiet --short HEAD || true)

  # 2. Make sure $target is checked out in the primary worktree
  if [[ "$current_branch" != "$target" ]]; then
    echo "Checking out $target…"
    git switch --quiet "$target" || git checkout "$target" || {
      echo "❌ Unable to switch to branch '$target'"; return 1; }
  fi

  # 3. Bail out if $target worktree is dirty
  if ! git diff-index --quiet HEAD --; then
    echo "❌ Target branch '$target' has uncommitted changes – aborting cleanup."
    [[ -n "$current_branch" && "$current_branch" != "$target" ]] && git switch --quiet "$current_branch"
    return 1
  fi

  # 4. Fast‑forward $target
  echo "Pulling latest commits into $target…"
  git pull --ff-only --quiet origin "$target" || {
    echo "❌ Pull failed – aborting cleanup."; return 1; }

  # 5. Get rid of stale worktree refs first
  git worktree prune

  # 6. Iterate over every local branch already merged to $target (except $target itself)
  git for-each-ref --format='%(refname:short)' --merged "$target" refs/heads |
    grep -v "^${target}$" |
    while read -r branch; do
      # Does this branch live in an active worktree?
      local wt_path
      wt_path=$(
        git worktree list --porcelain |
          awk -v b="refs/heads/$branch" '
            $1=="worktree" { w=$2 }
            $1=="branch"   && $2==b { print w }
          '
      )

      if [[ -n "$wt_path" ]]; then
        # Worktree exists – is it clean?
        if git -C "$wt_path" diff-index --quiet HEAD --; then
          echo "Fast‑forwarding branch $branch in worktree $wt_path…"
          if git -C "$wt_path" pull --ff-only --quiet; then
            echo "Removing clean worktree $wt_path (branch $branch)…"
            if git worktree remove "$wt_path"; then
              git branch -d "$branch"
            else
              echo "⚠️  Couldn’t remove worktree $wt_path – skipping branch deletion"
            fi
          else
            echo "⚠️  Couldn’t pull branch $branch – skipping"
          fi
        else
          echo "⚠️  Skipping $wt_path (branch $branch) – uncommitted changes present"
        fi
      else
        # No worktree. Just delete the local branch (already merged).
        git branch -d "$branch"
      fi
    done

  # 7. Return to original branch if needed
  if [[ -n "$current_branch" && "$current_branch" != "$target" ]]; then
    git switch --quiet "$current_branch"
  fi

  echo "✅ Cleanup complete."
}