hah, i used it once a Loooooooong time ago. To be sure, whether or not it's Unix or Linux, try different things that are different on either one. try the sleep command with a fraction of a second, like "sleep .5" if it works it Linux. try "ifconfig" alone, if it's Unix it will pull down the help menu, if it's Linux you will see the device list as if you typed "ifconfig -a" (default) etc. cat the /etc/issue file for info, or try uname.
