Script to list and optionally delete stale Git branches

git-stale-branches.sh

#!/bin/bash

# Configuration variables
REFERENCE_BRANCH="master"  # Branch to compare against
AGE_THRESHOLD_DAYS=180     # Number of days to consider a branch stale

DELETE_BRANCHES=false
CURRENT_DATE=$(date +%s)
if [[ "$(uname)" == "Darwin" ]]; then
  DATE_CMD="date -r"
else
  DATE_CMD="date -d @"
fi

# Helper function to calculate the difference in days between two dates
days_between() {
  local start=$1
  local end=$2
  echo $(( (end - start) / 86400 ))
}

if [[ "$1" == "--delete" ]]; then
  DELETE_BRANCHES=true
  echo "Running in delete mode. Identified branches will be deleted."
fi

git fetch --all --prune
remote_branches=$(git branch -r --format='%(refname:short)' | grep -v "$REFERENCE_BRANCH")

for branch in $remote_branches; do
  ahead=$(git rev-list --count "$REFERENCE_BRANCH..$branch")

  if [ "$ahead" -eq 0 ]; then
    last_commit_date=$(git log -1 --format="%ct" "$branch")
    branch_age_days=$(days_between "$last_commit_date" "$CURRENT_DATE")

    if [ "$branch_age_days" -ge "$AGE_THRESHOLD_DAYS" ]; then
      formatted_date=$($DATE_CMD "$last_commit_date" "+%Y-%m-%d %H:%M:%S")
      echo "Branch: $branch | Age: $branch_age_days days | Last Commit: $formatted_date"

      if [ "$DELETE_BRANCHES" = true ]; then
        remote_name=$(echo "$branch" | cut -d'/' -f1)
        branch_name=$(echo "$branch" | cut -d'/' -f2-)

        # Delete the branch both locally and remotely
        echo "Deleting branch $branch_name from remote/$remote_name and local..."
        git push "$remote_name" --delete "$branch_name"
        git branch -d -r "$branch" || echo "No local tracking branch to delete for $branch."
      fi
    fi
  fi
done

This will list out all stale Git branches in a repository. By "stale", I mean older than X days (180 by default) and with no commits ahead of the main / master branch.

If run with --delete, these branches will also be deleted from remote and local.