def get_user_input(username, session_id):
    """ Prompt and get a command from the user.

    Arguments:
        :username: The username of the user.
        :session_id: The session number incremented each time asking for inputing a command.
    Returns:
        The string command the user entered.
    """
    print('\nrf [n]: read file content [with last n lines], q: quit')
    return input(f'[{session_id:^3}@{username}] $ ')