Okay, you're out of my league - I didn't know one could run PHP outside of an HTTP environment.
But what I can do to help is give you the value of that variable on all the types of systems I have access to. On my WinXP running Apache, it says:
Apache/1.3.20 (Win32) PHP/4.1.0
On one hoster's FreeBSD server, it says:
Apache/1.3.33 (Unix) PHP/4.3.10 FrontPage/5.0.2.2623
On a different hoster's Linux server, even though it is also running PHP, it simply says:
Apache/1.3.34 (Unix)
On yet another (yes, I deal with a lot of hosters!), it is quite verbose:
Apache/1.3.33 (Unix) mod_throttle/3.1.2 DAV/1.0.3 mod_fastcgi/2.4.2 mod_gzip/1.3.26.1a PHP/4.4.2 mod_ssl/2.8.22 OpenSSL/0.9.7e
Sorry, I have no Macs to try it on, but then again, does anyone use a Mac as a web server?
If you call phpinfo(), you will see a huge list of system variables and their values - I have found that very helpful when deciding what variables to use to get the information I need.