Most newbies ponder the question, “what version of redhat am I actually running?”.
# uname -a
will give you a load of useful information; but not, say, “CentOS 4.3″.
It is rather simple, simply type the following command (without #):
# tail /etc/redhat-release
This will output something like: CentOS release 4.4 (Final)
And you’re good to go!