Learning Unix for OS X

Preface

It’s been a long time since we went through the transition from Mac OS 9 to the more complicated and graphically rich world of OS X. Many of you reading this have never known a Mac interface that wasn’t actually OS X (pronounce that “oh-ess ten” to sound cool). The biggest change when Apple switched operating systems was that every machine then gained multitasking and multiuser capabilities.

What you might not have realized, however, is that it was the underlying operating system itself that changed in the update to OS X, and that you have a tremendously powerful OS that can run thousands of open source applications downloaded free from the Net, along with a command-line interface that makes even the most complex tasks a breeze.

If you want to learn the key phrases, beneath OS X lies an operating system called Unix (pronounced “you-nicks”): specifically, UC Berkeley’s BSD Unix and the Mach kernel, a multiuser, multitasking operating system. Being multiuser means OS X allows multiple users to share the same system, each with their own settings, preferences, and separate area in the filesystems, secured from other users’ prying eyes. Being multitasking means OS X can easily run many different applications at the same time, and if one of those applications crashes or hangs, the entire system doesn’t need to be rebooted. Instead, you just force quit the application that’s causing the “Spinning Beach Ball of Death” (you know, when the mouse pointer turns into a spinning color wheel ...