Introduction: #52-70

Using Linux effectively is a learning process. One of the best ways to learn is to just dive in and try it. If you are new to Linux, you quickly discover another good way to learn is to fix something you accidentally broke. I consider myself an experienced Linux administrator; by "experienced," I mean that I have broken my system many times and have had to recover it.

The most frustrating mistake you can make under Linux is one that leaves your computer unbootable. Like with most things in Linux, there are a number of ways that you can do this, and once you do, you will need a rescue disk. Many distributions include special-purpose rescue disks, or the install CD itself doubles as a rescue disk. This works well enough when you need to recover some common mistakes on that particular distribution, but none of the distribution rescue disks come close to the flexibility and number of tools Knoppix includes to fix Linux. Besides, many distribution recovery CDs provide only a command prompt. Knoppix provides a full GUI and a number of very useful GUI tools for repairing mistakes. With Knoppix, it's easy to open a web browser or a chat client and search for help.

The first part of this chapter includes many different tips for repairing the Master Boot Record (MBR), including how to restore both lilo and grub, and how to back up and restore your entire MBR. The next part of the chapter is focused on overall disk repair, and covers how to undelete files you have accidentally removed, methods to back up and restore files, and even a complete set of hacks for software RAID. The final set of hacks focus on how to repair some important system files that can stop your system from booting, including the /etc/passwd file and the kernel.

By the end of this chapter, you should be a master of Linux system recovery and be the "go to" guy your friends call when they break their machines.