Checking what version of Ubuntu you are running is very easy. From my own experience, there are multiple ways to check the Ubuntu version. You can either check from graphical interface version, or from command line in the local terminal session or via SSH. The following result has been tested from the command line that was run from the command remotely over SSH.
1. Check ubuntu version using “cat /etc/issue” command :
ehowstuff@ubuntu14:~$ cat /etc/issue
Ubuntu 14.04 LTS \n \l
2. Check Ubuntu version using “cat /etc/lsb-release” command :
ehowstuff@ubuntu14:~$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=14.04
DISTRIB_CODENAME=trusty
DISTRIB_DESCRIPTION=”Ubuntu 14.04 LTS”
3. Check Ubuntu version using “lsb_release -a” command :
ehowstuff@ubuntu14:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 14.04 LTS
Release: 14.04
Codename: trusty
or you can have more option to filter out the result :
ehowstuff@ubuntu14:~$ lsb_release -d
Description: Ubuntu 14.04 LTS
ehowstuff@ubuntu14:~$ lsb_release -c
Codename: trusty
ehowstuff@ubuntu14:~$ lsb_release -r
Release: 14.04
Additionally, you can check all the info regarding the kernel version :
ehowstuff@ubuntu14:~$ uname -a
Linux ubuntu14 3.13.0-24-generic #46-Ubuntu SMP Thu Apr 10 19:11:08 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
or
ehowstuff@ubuntu14:~$ cat /proc/version
Linux version 3.13.0-24-generic (buildd@panlong) (gcc version 4.8.2 (Ubuntu 4.8.2-19ubunt