As a Linux user, you might have come across a long text that starts with “I’d like to interject for a moment. What you are referring to as Linux, is in fact, GNU/Linux”.
It makes some people confused about what is Linux and what is GNU/Linux. I have explained it in the article about the concept of Linux distributions.
Basically, Linux is a kernel and with GNU softwares, it becomes usable in the form of an operating system.
Many purists and enthusiasts don’t want people to forget the contribution of GNU to the Linux-based operating systems. Hence, they often post this long text (known as GNU Linux copypasta) in various forums and communities.
I am not sure of the origin of the GNU/Linux copypasta and since when it came into existence. Some people attribute it to Richard Stallman’s article on GNU blog in 2011. I cannot confirm or deny that.