Mac OS X Lion: The Missing Manual

Terminal

The keyhole into Mac OS X’s Unix innards is a program called Terminal, which sits in your Applications→Utilities folder (see Figure 16-2). Terminal is named after the terminals (computers that consist of only a monitor and keyboard) that used to tap into the mainframe computers at universities and corporations. In the same way, Terminal is just a window that passes along messages to and from the Mac’s brain.

The first time you open Terminal, you’ll notice that there’s not much in its window except the date, time and source of your last login, and the command line prompt (Figure 16-2).

UP TO SPEED: Mac OS X’s Unix Roots

In 1969, Bell Labs programmer Ken Thompson found himself with some spare time after his main project, an operating system called Multics, was canceled. Bell Labs had withdrawn from the expensive project, disappointed with the results after four years of work.

But Thompson still thought the project—an OS that worked well as a cooperative software-development environment—was a promising idea. Eventually, he and colleague Dennis Ritchie came up with the OS that would soon be called Unix (a pun on Multics). Bell Labs saw the value of Unix, agreed to support further development, and became the first corporation to adopt it.

In the age when Thompson and Ritchie started their work on Unix, most programmers wrote code that would work on only one kind of computer (or even one computer model). Unix, however, was one of the first portable operating systems; its programs ...