How To Determine OS Version on Your Raspberry Pi

Someday you may realise that you had your Raspberry Pi for so long that you no longer remember what OS release it's running.

Turns out, it's super easy to double-check:

root@s7:~# cat /etc/os-release
PRETTY_NAME="Raspbian GNU/Linux 8 (jessie)"
NAME="Raspbian GNU/Linux"
VERSION_ID="8"
VERSION="8 (jessie)"
ID=raspbian
ID_LIKE=debian
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums" 
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"