12.5 X and the Shell

You can configure your system to boot into nongraphical mode, if you prefer. If your video adapter is not compatible with X, you have no alternative but to do so. However, some Linux users having X-compatible video adapters prefer to configure their system to boot into nongraphical mode. A simple command lets such users launch an X session whenever they wish.

12.5.1 Configuring a Nongraphical Login

Linux provides several runlevels. Each runlevel has an associated set of services. For instance, runlevel 3 is associated with a text-based login and run level 5 is associated with an X-based, graphical login. Changing runlevels automatically starts and stops services associated with the old and new run levels.

You can determine the current runlevel by issuing the following command:

# runlevel

The output of the command shows the previous and current runlevels. For example, the output:

3 5

indicates that the current run level is 5 and that the previous run level was 3.

To change the current runlevel, issue the init command. For example, to enter runlevel 3, issue the following command while logged in as root:

# init 3

In response to this command, the system will start and stop services as required to enter runlevel 3.

The /etc/inittab file specifies the default runlevel, which the system enters when booted. By changing the default run level to 3, you can configure your system to provide a nongraphical login when it boots. To do so, log in as root and load the /etc/ inittab file into the nano editor by issuing the command:

# nano /etc/inittab

Find the line that reads:

id:5:initdefault:

Change the 5 to a 3:

id:3:initdefault:

Save the file and exit nano. The next time you boot your system, it will automatically enter runlevel 3 and provide a nongraphical login screen.

12.5.2 Starting and Stopping X from a Text-Based Login

To start X from a text-based login, type the command:

$ startx

Your system's screen should briefly go blank and then you should see X's graphical desktop.

If the screen is garbled or remains blank for more than about 30 seconds, your X configuration may be faulty. Immediately turn off your monitor or terminate X by pressing Ctrl-Alt-Backspace.

When running X from a text-based login, you can gracefully quit X by merely exiting the desktop. To do so, select Logout from the main menu. To quit X abruptly, press Ctrl-Alt-Backspace.