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!) programs automate jobs you'd have to do manually and repetitively with a window system (unless you understand how to program a window system, which is usually a much harder job). See Section 10.3 in Chapter 10 for a brief introduction to scripting.

• In general, text-based interfaces are much easier than GUIs for sight- impaired users.

We aren't saying that the command-line interface is right for every situation. For instance, using the Web ”with its graphics and links ”is usually easier with a GUI web browser within Mac OS X. But the command line is the fundamental way to use Unix. Understanding it will let you work on any Unix system, with or without windows. A great resource for general Mac OS X information (the GUI you're probably used to) can be found in Mac OS X: The Missing Manual by David Pogue (Pogue Press/O'Reilly).