script.py

import argparse

if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("--name", help="Any name", default="inconnu")
    parser.add_argument("action", help="Action to execute")

    args = parser.parse_args()

    if args.action == "hello":
        print(f"Hello {args.name}")
    elif args.action == "goodbye":
        print(f"Goodby {args.name}")
    else:
        print(f"Unrecognized action {args.action}")