Mac OS X Snow Leopard: The Missing Manual (Missing Manuals)

Chapter 16. Terminal: Doorway to Unix

As you're certainly aware by now, Mac OS X's resemblance to the traditional Mac operating system is only superficial. The engine underneath the pretty skin is utterly different. In fact, it's Unix, one of the oldest and most respected operating systems in use today.

The first time you see it, you'd swear that Unix has about as much in common with the traditional Mac OS as a Jeep does with a melon (see Figure 16-1).

What the illustration at the bottom of Figure 16-1 shows, of course, is a command line interface : a place where you can type out instructions to the computer. This is a world without icons, menus , or dialog boxes; even the mouse is almost useless.

Surely you can appreciate the irony: The brilliance of the original 1984 Macintosh was that it eliminated the command line interface that was still the ruling party on the computers of the day (like Apple II and DOS machines). Most non- geeks sighed with relief, delighted that they'd never have to memorize commands again. Yet here's Mac OS X, Apple's supposedly ultramodern operating system, complete with a command line! What's going on?

Actually, the command line never went away. At universities and corporations worldwide, professional computer nerds kept right on pounding away at the little C : or $ prompts, appreciating the efficiency and power such direct computer control afforded them.

You're forgiven if your reaction to learning Unix is, "For goodness' sake ”can't I finish learning one way to control my new operating system before I have to learn yet another one?"

Absolutely. You never have to use Mac OS X's command line. In fact, Apple has swept it far under the rug, obviously expecting that most people will use the beautiful icons and menus of the regular desktop. There are, however, some tasks you can perform only at the command line, although fewer with each release of Mac OS X.

For intermediate or advanced Mac fans with a little time and curiosity , however, the command line opens up a world of possibilities. It lets you access corners of Mac OS X that you can't get to from the regular desktop. It lets you perform certain tasks with much greater speed and efficiency than you'd get by clicking buttons and dragging icons. And it gives you a fascinating glimpse into the minds and moods of people who live and breathe computers.

If you've ever fooled around with ResEdit, experimented with AppleScript, or set up a Mac on a network, you already know the technical level of the material you're about to read. The Unix command line may be unfamiliar , but it doesn't have to be especially technical, particularly if you have some "recipes" to follow like the ones in this chapter and the next .