How to Check Ubuntu Version in Terminal

I just curious about how to check Ubuntu version via Terminal. Since I often remote a server and I don't know what version is. Here is the command:

lsb_release -a

Then it will print out some messages like this:

No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 11.04
Release: 11.04
Codename: natty

So I has already know what Ubuntu version used in server. It is Natty. Enjoy!