def chmod(mode, file_name, options=""):
    """
    Applies the chmod command.
    
    :type mode: string
    :param mode: New mode of the destination. Typical examples are: a+r to give read permissions to everyone, a+rx to give execution and read permissions to any user, etc.

    :type file_name: string
    :param file_name: Destination of the new mode.

    :type options: string
    :param options: Optional set of parameters for this command.   
    """
    return ["chmod " + options + " " + mode + " " + file_name]