From Linux magazine, an article by Jeremy Zawodny: Everything is UNIX.
For me, this is an example of the "Miller meme" from Repo Man. "Suppose you're thinkin' about a plate o' shrimp. Suddenly someone'll say, like, "plate," or "shrimp," or "plate o' shrimp" out of the blue, no explanation." You go through life thinking you'll find something better than UNIX. The man pages still have the same bad examples and incomplete option descriptions as in 1984. The window systems aren't up to snuff for desktop use. People are still finding performance bottlenecks due to system architecture, whichever architecture your favourite UNIX flavour uses.
And then you realize, there really is not much more. Everywhere you look, the same point is reinforced over and over. Windows Vista comes along, OS X is built on a UNIX base, and you get past your long-standing resentment about X11. You read the documentation for the latest and greatest web framework, and you think to yourself, this isn't any more usable than those thrown-together man pages. Regardless of the fact that no system incorporates every possible performance boost, the systems taking advantage of the latest and greatest hardware are often descendants of UNIX; and if you're looking for mainframe-style reliability, again you're probably tinkering around in the UNIX space.
I find it interesting that UC Berkeley interrupts their Scheme-based intro to programming languages with an interlude to consider UNIX shell scripting. If the problem by combining a set of well-understood and reliable steps, don't reinvent the wheel. That's a good lesson for people developing frameworks and class libraries.
In the sample Google interview questions floating around the web, one recurring theme I've noticed is how to solve a fairly large-scale problem involving string and file manipulation. To which the obvious answer, IMHO, is to use the basic UNIX commands up to and including simple Perl scripts. For something quick and general-purpose, you're not going to implement a better string-finding algorithm than grep or a better simple sort than sort. Or a better I/O pipeline than UNIX pipes, or better filesystem traversal than find, or a better use of a huge memory space than a simple Perl hash. If you're writing complicated custom code, you'd better be solving harder problems than those.
(Hat tip to Tim Bray for the article.)