what is a UUID?

I recently just installed a not so recent Ubuntu distro (8 point something...) and found the fstab to be a little more cryptic than I remembered. Basically instead of the standard /dev/sda* that I knew, it listed a:

UUID=somelonghexadecimalstringwithdashes

After a bit of search, I found that this was called a Universally Unique Identifier. In short, it allows us to identify the disk partition with the knowledge that it won't be mistaken for something else. At least that's what the wiki page tells me. :) So I'm not really sure why this works, but at least I now know what that thing is.

To list the UUIDs for your devices, just run:

sudo blkid

Here's the relevant link on the Ubuntu help pages on fstab.

You learn something new everyday, eh? :)