#!/bin/bash set -e # Use the USER_ID environment variable or default to 1000 USER_ID=${USER_ID:-1000} # Check if the user already exists if id "$USER_ID" >/dev/null 2>&1; then echo "User with ID $USER_ID already exists." else echo "Creating user with ID $USER_ID." # Create a new user with the specified ID useradd -m -u "$USER_ID" user fi # Run the CMD or any other command you want to execute exec "$@"