Shell version of php

Hi guys, This arose trying to install php-egg, altho thats not what this msg is really about. For it to run I need to have "a shell version" running... what exactly is this and how do I go about installing it? I have php installed (I think) as a module.. and by my understanding this is necessary for certain functions to run.... can I have both co-existing? I guess what I want is a copy of php running completely separate to apache, ie as a standalone app......... any help much appreciated!!! Tom Carter