The Heart of Unix
Despite all of its warts, I like working in Linux. I've used it for 15 years and I've never been as productive in another environment. Most people claim that it's the configurability of Linux that keep the users coming. That may have attracted me at first, but what attracts me now is its programmability.
Let me be very clear. I'm not saying that Linux is great because I can patch the source code to grep and recompile it. In all my years of Unix, I've never done anything like that. And I'm not saying that Linux is a great workstation for programmers because it helps you program better. Those are topics for another essay.
I am saying that Unix is a programmable environment. When you interact with the shell, you are writing programs to be interpreted. You can easily extend the Unix system by writing a shell script, copying it to a directory in your PATH, and making it executable. Boom. You've got a new program.
What's more, that program, if it follows certain simple conventions, is now able to work with other programs. Those conventions are simple, and they are summed up well by Doug McIlroy, the inventor of Unix pipes:
