There are certain commonly used operations in X that you should familiarize yourself with. This section describes some of the basic operations that you may find useful.
The mouse in X works pretty much the same as the mouse on other systems, except that it has three buttons. If your mouse has only two, you can simulate the middle button by clicking both buttons simultaneously. This is kind of tricky and annoying, so investing in a $15 three-button mouse probably isn't a bad idea. These are available from most computer retailers.
The buttons are numbered from left to right assuming you have a right-handed mouse. So button one is on the left, two is in the middle, and three is on the right. You may see either the numbers or the locations in documentation.
X has a simple built-in copy-and-paste facility. To select text to copy, you click and drag with the left mouse button. This should select the text to copy, assuming the application you're using has copy-and-paste support. To paste the text, you click the middle mouse button in a different X application. For example, if you receive an e-mail containing an URL, you can select the URL with the left button and then click in your web browser's ``Location'' field with the middle button to paste it in.
Programs that communicate with the X server are called X clients. Most of these programs will ask the X server to display windows on the screen.
You start an X client the same way you start any other Debian program. Simply type the name of the client on the command line. Try typing xterm into an existing xterm window, and a new xterm client will appear on the screen.
You may notice that the original xterm is now useless, because your shell is waiting for the second xterm to finish. To avoid this problem, you can run the X client in the backgroundby adding a & after the command name like this: xterm &. If you forget, you can place a running process in the background. First suspend the process with CTRL-z, and then place it in the background with the bg command.
If you use a program often, your window manager will generally provide a way to put that program on a convenient graphical menu.
Sometimes when you launch an X client from a graphical menu, you won't be able to see any error messages if it fails. You can find any error messages in the file ~/.xsession-errors.
To leave X, you need to use a menu. Unfortunately for beginners, this is different for every window manager, and for most window managers, it can be configured in many ways. If there's an obvious menu, look for an entry like ``Exit'' or ``Close Window Manager.'' If you don't see a menu, try clicking each of the mouse buttons on the background of the screen. If all else fails, you can forcibly kill the X server by pressing CTRL-ALT-Backspace. Forcibly killing the server destroys any unsaved data in open applications.