Once Upon a Time...
...Two well-known computer junkies named Brian W. Kernighan and Rob Pike wrote a book called The Unix Programming Environment (1984, ISBN 0139376992) and here are two quotes that foreshadow issues-to-come (p. 1):
"What is 'UNIX'? In the narrowest sense, it is a time-sharing operating system kernel: a program that controls the resources of a computer and allocates them among its users."
Okay, so UNIX=kernel. However, in the next paragraph, Kernighan and Pike say (p. 1):
"In a broader sense, 'UNIX' is often taken to include not only the kernel, but also essential programs like compilers, editors, command languages, programs for copying and printing files, and so on."
Erm, so it can also be used to denote a kernel PLUS an "environment" built around a kernel.
The GNU Project and the Linux Kernel
Back in the 1980s, around the time The Unix Programming Environment was published in fact, Richard Stallman started the GNU Project to build a free-as-in-freedom-not-as-in-beer "operating system" in the broader sense, a bunch of GNU tools sitting on top of "The Hurd" which in turns sits atop the GNU Mach microkernel. This GNU Operating system never came to be, partly because the Mach-plus-Hurd system proved difficult to create, partly because another kernel came along and most work moved to this new kernel.
In 1991 Linus Torvalds released his Linux kernel (there's a history behind this name too: the "working name" of the project was apparently "Linux" for Linus's UNIX (or MINIX, which is actually what he "cloned"), and Linus wanted to call it "Freax," but Ari Lemmke kept the Linux name). Linux wound up under the GPL v. 2 (with no "and later..." clause), it was (still is) compiled with gcc, and the GNU tools were set atop this kernel to become...
Depending on who you ask, either "Linux" or "Gnu\Linux" (read Gnu-slash-Linux).
Stallman insists on including "GNU" in the name. The "received view" is that this is a purely semantic debate. There is a precedence for, in practice, using the name of a kernel to designate an entire "operating system," as the opening Kernighan and Pike quote demonstrates. Some people insist on calling the system "Linux" for pragmatic or aesthetic reasons, for instance in the Linux (or Gnu\Linux...) manual How Linux Works by Brian Ward, Ward says "I've tried to use the most common, least awkward names possible." (p. xxii, ISBN 9781593275679).
Some people try to rank the parts of an operating system by importance and insist on using the name that best reflects these important parts. Stallman insists that Linux is a small piece of the Gnu\Linux ecosystem, emphasizing the tools and compiler. In contrast, William F. Shotts, in his book The Linux Command Line, insists that Linux\GNU "would be more technically accurate since the kernel boots first and everything else runs on top of it." (p. xxix, ISBN 9781593273897). Since there is now a major Linux distro that does not rely on the GNU bits -- it's called Android -- the pragmatic reasons for a distinction between GNU\Linux and Other\Linux has kind of got a boost.
In a 1996 post by Linus Torvalds, reprinted in Peter H. Salus's The Daemon, The Gnu, and the Penguin: A History of Free and Open Source (pp. 143-4, ISBN 9780979034237), Linus says:
It doesn't really _ matter _ what people call Linux, as long as credit is given where credit is due (on both sides). Personally, I'll very much continue to call it "Linux"...
The Issue of Visibility
What's sometimes overlooked is that there is another reason to insist on including "GNU" in the name, and that's the issue of visibility. Richard Stallman has a philosophy to articulate and an organization to promote. He wants people to know the name of his organization, he wants people to participate, to use and share the GNU tools, provide donations, the works, so of course Stallman wants "GNU" in the name. In an article called GNU Users Who Have Never Heard of GNU, Stallman laments the fact that many people who use GNU tools on a daily basis have never heard of GNU. Just about everyone these days has heard of Linux.
This kind of promotion, corny as it may sometimes seem, works. Hearing about the GNU/Linux Naming Controversy made me want to know more about GNU and the FSF. I knew vaguely about Richard Stallman as a hippy meme who eats stuff from between his toes, but only as a result of getting to the bottom of this pesky GNU\Linux business did I read things like his collection of essays Free as in Freedom. A quasi-mythical Stallman dogmatist (a Stallmaniac, if you will) dominates discussion of this topic, so hard-headed things like the fact that he decided to articulate his philosophical vision primarily via a legal document, or things like the "matter of strategy" that is the Lesser GPL don't get the airing they deserve.
Stallman's ideas continue to have real impact, and he's not alone in articulating a "free culture" sort of vision. In fact, Free Culture is the name of a book by Lawrence Lessig, Roy L. Furman Professor of Law at Harvard, founder of Creative Commons, and unsuccessful 2016 presidential candidate. In this book, Lessig says:
The inspiration for the title and for much of the argument of this book comes from the works of Richard Stallman and the Free Software Foundation. Indeed, as I reread Stallman's own work, especially the essays in Free Software, Free Society, I realize that all of the theoretical insights I develop here are insights Stallman described decades ago.
In practice I wind up using "Linux" quite often, but I'm increasingly smitten with the FSF vision, so I just might join the persistent GNU\Linux crowd.
Or...and this thought tickled my sense of mischief...what if we give it a name that excludes both GNU and Linux, like Ginux (gee-nix)? That would be...funny. Just a thought.
Nearly twenty years after the release of the Linux kernel this topic still excites (and perhaps overexcites) people. Bryan Lunduke recently wrote a joke article in The Linux Journal called Why Linux is Spelled Incorrectly in which he concludes "Linux" should be spelled "Linucs" like the old MULTICS that UNIX (and hence MINIX and hence Linux) is based on. As of March 15, 2018, there are 123 comments on the article. Some people took it very seriously, and Mr. Lunduke felt the need to make a YouTube video response to the "controversy." This issue will vex FLOSS nerds FOREVER.