Hack 3 Use Knoppix Cheat Codes

Cheat codes are extra instructions you type at boot time that change many of Knoppix's settings. On some hardware, use of these codes may be necessary to get the most out of Knoppix.

Knoppix is good at automating many of the tasks that Linux users often conduct manually, such as hardware configuration, setting up the network, and logging into a desktop. If you want to customize options or change what Knoppix automatically runs, you can enter special commands at the boot prompt, which Knoppix refers to as cheat codes. Cheat codes are a reference to the secret passwords or key sequences entered in video games to get unlimited lives or other special items. Fortunately, cheat codes in Knoppix are simple words you type at the boot prompt, and not complicated joystick sequences like up, down, up, down, left, right, left, right, B, A. The cheat codes aren't secret either. Open the Knoppix CD under your current OS and browse to the KNOPPIX directory. The cheat codes file is called knoppix-cheatcodex.txt. You can also reference a list of the most frequently used cheat codes by pressing F2 at the boot prompt.

To use cheat codes at the boot prompt, type knoppix to select the default kernel, followed by the cheat codes you wish to use. For example, if your Knoppix CD doesn't work the way you expect, test for any physical errors on the disc; at the boot: prompt, type the following command:

knoppix testcd

The following table lists many of the settings and options you can change from the boot: prompt using cheat codes:

Cheat code	Purpose
knoppix testcd	Check CD data integrity and MD5sums
knoppix desktop=fluxbox|icewm| kde|larswm|twm|wmaker|xfce	Use specified window manager
knoppix 2	Runlevel 2, Textmode only
knoppix noeject	Do NOT eject CD after halt
knoppix noprompt	Do NOT prompt to remove the CD
knoppix splash	Boot with fancy background splashscreen

For example, if you want to use the fluxbox window manager instead of the default KDE desktop, at the boot: prompt type:

knoppix desktop=fluxbox

Look at the list of cheat codes to see a number of other window managers, including icewm, larswm, twm, wmaker, and xfce. Each of these window managers offers different features, and most of them offer a completely different environment from what a Windows user might be used to. In addition, these other desktop environments load faster and use less memory than the default KDE desktop.

The text mode cheat code (type knoppix 2 at the boot: prompt) is useful in circumstances when you don't need a full graphical environment or your graphical environment does not work. This cheat code goes through the full hardware detection but leaves you at a simple prompt instead of launching a desktop environment. On machines with less than 64 MB of RAM (less than 82 MB if using KDE), this mode lets you boot into Knoppix and take advantage of all of Knoppix's command-line utilities—just without the desktop environment. This mode is also useful because it quickly boots into a full shell without the wait for X and a desktop environment to load. After you boot into text mode, you can switch into a full desktop environment by changing your runlevel; at a prompt, type the following command, and Knoppix will start up the default desktop environment:

root@tty1[/]# init 5

The splash cheat code adds some extra eye candy to the boot process. This cheat code replaces the colorized text output with a fancier graphical background as the system is booting, reminiscent of loading Windows. Hit the Esc key to drop back to the default text output.

The noeject and noprompt cheat codes are useful when, the next time you boot, you plan to use the Knoppix CD in the same system. By default, when Knoppix shuts down, it ejects the CD and prompts you to hit Enter to complete the shutdown. Use these cheat codes to disable these two convenience features, and when Knoppix shuts down, it leaves the CD in the drive for the next boot.

Experiment! Try out new desktops. Test different cheat code combinations. Remember that changes you make with cheat codes do not persist across reboots, and desired changes must be entered at the boot: prompt each time. To make settings persistent, save them on media, such as a USB drive, a floppy diskette, or an existing hard drive. (Saving persistent settings is covered in detail in [Hack #21] .)