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!) ...