ID:135713
 
Now that we have quite a few different version of the BYOND engine running on different OS's it would be nice to determine what version of the program they are using, probably something like client.byond_version, then it could be MacOSX, Linux, FreeBSD or Windows. :) Hope its considered as it can't be a real time consumer to implement.
http://www.byond.com/docs/ref/info.html#/world/var/ system_type

I'm not sure if there's any real benefit to differentiating between the various Unix versions. If you really must know, you can find that out in trusted mode with a shell() to call uname.
In response to Mike H (#1)
I thought about world.system_type, too.. but Maz's looking for a client.system_type, it seems.