If you have several machines running Ubuntu, or several versions installed on the same machine, you may, like me, sometimes forget what version you have are running presently. A quick and easy way to do this is with the following command:
lsb_release -a
An example of the output on my system is as follows:
peter@peeeter-karmic:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:?? ?Ubuntu 9.10
Release:?? ???? 9.10
Codename:?? ??? karmic
The personal blog of Peter Nikolaidis