Learning Unix for Mac OS X, Second Edition

Interfaces to Unix

Unix can be used as it was originally designed: on typewriter-like terminals, from a prompt on a command line. Most versions of Unix also work with window systems (or GUIs). These allow each user to have a single screen with multiple windows — including “terminal” windows that act like the original Unix interface.

Mac OS X includes a simple terminal application for accessing the command-line level of the system. That application, reasonably enough, is called Terminal and can be found in the Applications → Utilities folder. The Terminal application will be examined more closely in Chapter 1 and Chapter 2.

Although you can certainly use your Mac quite efficiently without typing text at a shell prompt, we’ll spend all our time in this book on that traditional command-line interface to Unix. Why?

• Every Unix system has a command-line interface. If you know how to use the command line, you’ll always be able to use the system.

• If you become a more advanced Unix user, you’ll find that the command line is actually much more flexible than a windowing interface. Unix programs are designed to be used together from the command line — as “building blocks” — in an almost infinite number of combinations, to do an infinite number of tasks. No windowing system we’ve seen (yet!) has this tremendous power.

• You can launch and close GUI programs from the command line.

• Once you learn to use the command line, you can use those same techniques to write scripts . These little (or big!) ...