Open a terminal program (get to a command prompt) and type uname -a. This will give you your kernel version, but might not mention the distribution your running. To find out what distribution of linux your running (Ex. Ubuntu) try lsb_release -a or cat /etc/*release or cat /etc/issue* or cat /proc/version.

Open a terminal program (get to a command prompt) and type uname -a. This will tell you the version (release) and type of BSD your running.