How can I establish the variation of the running kernel?
The main variation of an Ubuntu kernel is located in the
/proc/version_signature documents (mainline bits might lack this documents, in which instance
uname -r suffices).
This documents has both the complete Ubuntu variation of the kernel and also the mainline variation on which it is based. The first area is constantly Ubuntu, the 2nd area is the Ubuntu kernel variation, and also the last area is the upstream variation :
$ cat /proc/version_signature Ubuntu 2.6.35-6.9-generic 2.6.35-rc3