Learning the UNIX Operating System, Fourth Edition

Chapter 2. Using Window Systems

Introduction to Windowing

All versions of UNIX work with computer terminals that handle a single window or a single login session. Most modern UNIX versions support one or more window systems. A window system is a package of programs that let a terminal handle many sessions at once. Along with the keyboard, window systems use a mouse or another device (such as a trackball) to move a pointer across the screen. The pointer can select parts of the screen, move them, help you copy and paste text, work with menus of commands, and more. If you’ve used a Macintosh, any version of Microsoft Windows, or OS/2 and its Presentation Manager (among others), you’ve used a window system. Figure 2.1 shows a typical display with windows.

Here’s a special note for Linux users. Most Linux systems support window systems. But they also have a surprisingly handy substitute: virtual consoles. If you’re using the terminal that’s directly connected to a personal computer running Linux, you can access up to eight separate screens on the same display. To use virtual consoles, hold down the left ALT key and press one of the function keys F1 through F8. Each of those function keys will bring up a separate UNIX session with its own shell prompt. Use each one for whatever you want—just remember to log out from each virtual console when you’re done!

We won’t mention Linux virtual consoles any more. This chapter introduces the X Window System (called X for short), the most common ...