Started using Linux and StackExchange since Ubuntu 12.04 LTS. Then Upgraded to 14.04 LTS.

Now I am using Debian GNU/Linux on my Laptop and PureOS on old Desktop computer.

I recommend visiting the Philosophy of GNU Project

As I've replaced Ubuntu with Debian GNU/Linux, Now my question(s) are became off-topic on AskUbuntu. So, I continue to Unix & Linux.

The second reason for my shifting to U & L is I found U & L more interesting than AU since AU is only Ubuntu specific whereas U & L is a broad concept and in my opinion U & L deserves generic questions. (I know why SE has AU & U & L both).