start unity standalone on server from php

Is it possible to start a unity standalone on a server from php. I've been investigating the pieces so far but don't know if it's possible.

Php can start an exe from a server http://php.net/manual/en/function.exec.php

A unity standalone can accept command line arguments http://docs.unity3d.com/Manual/CommandLineArguments.html

and Unity can receive arguments from command line using the following code

 Using System;
 String[] Data = Environment.GetCommandLineArgs();

I'm confused as to whether the php exec is the same as a command line call and whether any of this can be done.