'final' is introduced in PHP5. Final class means that this class cannot be extended and a final method cannot be overridden.
PHP supports only single inheritance; it means that a class can be extended from only one single class using the keyword 'extended'.
Just use the PHP command line interface (CLI) and specify the file name of the script to be executed as follows:
PHP: Hypertext Preprocessor is a general-purpose programming language originally designed for web development. It was originally created by Rasmus Lerdorf in 1994; the PHP reference implementation is now produced by The