sudo apt-get install lsb-release

sudo apt-get install lsb-core

$ lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux 8.3 (jessie)
Release:    8.3
Codename:   jessie

LSB Version:    core-2.0-amd64:core-2.0-noarch:core-3.0-amd64:core-3.0-noarch:core-3.1-amd64:core-3.1-noarch:core-3.2-amd64:core-3.2-noarch:core-4.0-amd64:core-4.0-noarch:core-4.1-amd64:core-4.1-noarch:security-4.0-amd64:security-4.0-noarch:security-4.1-amd64:security-4.1-noarch
Distributor ID: Debian
Description:    Debian GNU/Linux 8.3 (jessie)
Release:    8.3
Codename:   jessie

cat /etc/lsb-release
cat /etc/os-release

ls -l /etc/*release*

hostnamectl

Static hostname: debian
       Icon name: computer
         Chassis: Laptop
      Machine ID: 4c983dae19f6403ca2c555c386cdeb14
         Boot ID: 3b399eb976d04569a8514a1dczdv4d81
Operating System: Debian GNU/Linux 8 (jessie)
          Kernel: Linux 3.16.0-4-amd64
    Architecture: x86-64