Which Linux version am I running?

I can't never remember which version of GNU/Linux I'm running on. I know I use Ubuntu but is it Gutsy Gibbon? Hoary Hedgehog? Feisty Fawn?

I just found out about a tool called lsb_release.

lsb_release is a tool created by the LSB (Linux Standard Base) that returns information about the distribution name, version, codename... So this tool should be available on most of the GNU/Linux distribution.

The output will look like this:

cyril@merlin:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 7.10
Release: 7.10
Codename: gutsy


Time to upgrade to Hardy Heron