If you are a software developer in your 20s or 30s, you've grown up in a world dominated by Linux. It has been a significant player in the data center for decades, and while it's hard to find definitive operating system market share reports, Linux's share of data center operating systems could be as high as 70%, with Windows variants carrying nearly all the remaining percentage. Developers using any major public cloud can expect the target system will run Linux. Evidence that Linux is everywhere has grown in recent years when you add in Android and Linux-based embedded systems in smartphones, TVs, automobiles, and many other devices.
Even so, most software developers, even those who have grown up during this venerable "Linux revolution" have at least heard of Unix. It sounds similar to Linux, and you've probably heard people use these terms interchangeably. Or maybe you've heard Linux called a "Unix-like" operating system.
So, what is this Unix? The caricatures speak of wizard-like "graybeards" sitting behind glowing green screens, writing C code and shell scripts, powered by old-fashioned, drip-brewed coffee. But Unix has a much richer history beyond those bearded C programmers from the 1970s. While articles detailing the history of Unix and "Unix vs. Linux" comparisons abound, this article will offer a high-level background and a list of major differences between these complementary worlds.
Unix's beginnings
The history of Unix begins at AT&T Bell Labs in the late 1960s with a small team of programmers looking to write a multi-tasking, multi-user operating system for the PDP-7. Two of the most notable members of this team at the Bell Labs research facility were Ken Thompson and Dennis Ritchie. While many of Unix's concepts were derivative of its predecessor (Multics[1]), the Unix team's decision