Each project can have its own configuration (you can have 1 project with a PHP5.4 interpreter, one of them is PHP5.6, one of which is a command line, and the other is a web project), but if you configure general PHP 5 Interpreter: 
If you are running on a Windows machine, you can use this code (php.cmd file name)
set XDEBUG_CONFIG="idekey=netbeans-xdebug" @php.exe %*
If you want to debug, your interpreter must have the XDEBUG_CONFIG system variable and make sure that it is connected to netbeans. You must set this value in your Debbugging section in your PHP configuration: 
The next is that if you right-click in the editor, you will have the Debug File option and a prompt window will appear:
You don't need anything here. Just click OK.
As you can see, this end result is a debugging session of the t1.php file in c:\TEMP\ (which is not a working draft):

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