Shell script to identify and list local Git branches merged upstream that can be deleted.

check_and_delete_merged_branches.sh

#!/bin/bash

# Update remote tracking branches
git fetch --prune

# Get the default branch name (e.g., main or master) from origin
DEFAULT_BRANCH=$(git remote show origin | grep 'HEAD branch' | awk '{print $NF}')

# Fallback if default branch cannot be determined
if [ -z "$DEFAULT_BRANCH" ]; then
  echo "Warning: Could not determine the default branch for 'origin'. Assuming 'main'."
  DEFAULT_BRANCH="main"
fi

echo "Checking for local branches merged into origin/$DEFAULT_BRANCH that can be deleted:"
echo "--------------------------------------------------------------------------"

# List local branches that are merged into the default remote branch
# Exclude the default branch itself and the currently checked out branch
git branch --merged "origin/$DEFAULT_BRANCH" | \
  grep -v "\*" | \
  grep -v "$DEFAULT_BRANCH" | \
  while read -r branch; do
    # Trim whitespace and print
    echo "  $(echo "$branch" | xargs)"
  done

echo "--------------------------------------------------------------------------"
echo "To delete these branches, you can use: git branch -d <branch_name>"
echo "Or for multiple branches: git branch --merged origin/$DEFAULT_BRANCH | grep -v '\*' | grep -v '$DEFAULT_BRANCH' | xargs git branch -d"