I'm not sure I get your question. Let me try to rephrase.

You have a file called 'hello_world.pl' with the content you have shown. On the command promt you type perl hello_world.pl and get the printed hello world as a return.

Now you would like to know how to get the text of the program printed out, instead of the program executed. This depends on your operating system. On Unix/Linux you type cat hello_world.pl and on Windows you type type hello_world.pl.

For how to do these things from perl, see the other answers.