You can execute:
uname -r
It will display something like
3.13.0-62-generic
Found on http://askubuntu.com/questions/359574/how-do-i-find-out-the-kernel-version-i-am-runninghttps://askubuntu.com/questions/359574/how-do-i-find-out-the-kernel-version-i-am-running (view that QA to learn other commands you could use)