Our network mainly runs on Ubuntu servers, especially for development. When trying to fix an issue or do an update I often need to know the version of Ubuntu installed on the server. Thankfully this is an extremely easy task, once you know where to look.
In terminal, output the contents of /etc /lsb-release like so:
cat /etc /lsb-release
Which will output something very similar to:
As you can see the release of Ubuntu on this server is Gutsy, Ubuntu 7.10. As far as I am aware all Ubuntu distros have the same release file.