How to check Ubuntu version

Below you can find some tips on how to check Ubuntu version you are currently running. The first place to look for Ubuntu version is to look inside /etc/issue file. From terminal run command:

$ cat /etc/issue
Ubuntu Xenial Xerus \n \l

To obtain a Ubuntu release number check content of /etc/lsb-release file:

$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu Xenial Xerus

Additional information regarding Ubuntu version can be found within /etc/os-release:

$ cat /etc/os-release
NAME="Ubuntu"
VERSION="16.04 (Xenial Xerus)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 16.04"
VERSION_ID="16.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
UBUNTU_CODENAME=xenial

Furthermore, the following command will provide you with a neat output of your current Ubuntu version:

$ lsb_release -da
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu Xenial Xerus (development branch)
Release:	16.04
Codename:	xenial

Lastly, systemd command hostnamectl reveals Ubuntu version along with some other relevant information such as kernel version and more:

 $ hostnamectl
   Static hostname: linuxconfig
         Icon name: computer-desktop
           Chassis: desktop
        Machine ID: 3b348a19c578436796b717d614b868b1
           Boot ID: 1ad07ee4476a466392fc8dfa423e3b11
  Operating System: Ubuntu 16.04
            Kernel: Linux 4.4.0-18-generic
      Architecture: x86-64

from https://linuxconfig.org/how-to-check-ubuntu-version