The Red Hat exams are an advanced challenge. As both the RHCE and RHCT courses specify a number of prerequisite skills, this book assumes that you know some basics about Linux. This chapter covers the prerequisite topics for Red Hat's RH300 course in a minimum of detail, with references to other books and sources for more information. It also covers the related prerequisites as defined in the Red Hat Exam Prep guide. Unlike those in other chapters and other books in this series, the questions in this chapter include a number of "zingers" that go beyond the chapter's content. These questions will help determine whether you have the prerequisite skills necessary to handle the remaining chapters.
If you're serious about the RHCE and RHCT exams, this chapter should be just a review. In fact, for any user serious about Linux, this chapter should be trivial. Linux gurus should recognize that I've "oversimplified" a number of explanations; my intention is to keep this chapter as short as possible. However, it is okay if you do not feel comfortable with a few topics in this chapter. In fact, it's quite natural that many experienced Linux administrators don't use every one of the prerequisite topics in their everyday work. Many candidates are able to fill in the gaps in their knowledge with some self-study and practice.
If you're new to Linux or Unix, this chapter will not be enough for you. It's not possible to provide sufficient detail, at least in a way that can be understood by newcomers to Linux and other Unix-based operating systems. If, after reading this chapter, you find gaps in your knowledge, refer to one of the following guides:
The Red Hat Enterprise Linux 5 documentation guides, available online from http://www.redhat.com/docs/manuals/enterprise/.
Hacking Linux Exposed, Third Edition: Linux Security Secrets and Solutions, by Casarik, Hatch, Lee, and Kurtz, gives you a detailed look at how to secure your Linux system and networks in every possible way.
Mastering Fedora Core 5, by Michael Jang, covers the distribution that Red Hat used as one of the testbeds for RHEL 5.
Critical to a Linux administrator is knowledge of one or more text editors to manage the many configuration files on a Linux system. The Linux filesystem hierarchy organizes hardware, drivers, directories, and, of course, files. You need to master a number of basic commands to manage Linux. Printer configuration can be a complex topic. Shell scripts enable you to automate many everyday processes. Security is now a huge issue that Linux can handle better than other operating systems, both locally and on larger networks such as the Internet.
As an administrator, you need a good knowledge of basic system administration commands, TCP/IP configuration requirements, and standard network services. While the RHCE and RHCT exams are by and large not hardware exams, some basic hardware knowledge is a fundamental requirement for any Linux administrator.
This is not a book for beginners to Linux/Unix-type operating systems. Some of what you read in this chapter may be unfamiliar. Use this chapter to create a list of topics that you may need to study further. In some cases, you'll be able to get up to speed with the material in other chapters. But if you have less experience with Linux or another Unix-type operating system, you may want to refer to the aforementioned books.
If you're experienced with other Unix-type operating systems such as Solaris, AIX, or HP-UX, you may need to leave some defaults at the door. When Red Hat developed its Linux distribution, it included a number of things that are not consistent with the standards of Unix (or even other Linux distributions). When I took the RH300 course, some students with these backgrounds had difficulties with the course and the RHCE exam.
In this book, most commands are run as the Linux administrative user, root. Logging in as the root user is normally discouraged unless you're administering a computer. However, since the RHCE and RHCT exams test your administrative skills, it's appropriate to run commands in this book as the root user.
While this chapter is based on the prerequisites described at https://www.redhat.com/training/rhce/courses/rh300_prereq.html, there are several additional prerequisite skills defined in the Red Hat Exam Prep guide at https://www.redhat.com/training/rhce/examprep.html.
For the RHCE and RHCT exams, the skills outlined in this chapter are generally minimum requirements. For example, while you may prefer to use an editor other than vi, you may not have access to the GUI, and therefore need to know how to use a console-based text editor on at least the Troubleshooting and System Maintenance section of the exam. While you're not required to know how to pipe the output of dmesg to the less command, this is a useful tool that can help you identify problems.
Remember that there are more ways than one to do most everything in Linux. While it's best if you learn all of these "prerequisite" skills, you don't have to know everything in this chapter. In most cases, it's okay if you use other methods of editing or otherwise configuring your RHEL 5 system. As the Red Hat exams no longer include multiple choice questions, don't worry about memorizing the dozens of switches used for certain commands. Focus on results, not trivia.
Using Other Versions of Red Hat
For those of you with more advanced hardware experience, the Red Hat exams are based on PCs built with Intel 32-bit CPUs. That means you'll be using the Linux kernel and associated software that has been customized for this CPU.
For the purpose of this chapter, you can use Fedora Core 6 or one of the rebuild distributions to test your knowledge of basic commands. In fact, the rebuild distributions are excellent, freely available options, as they use the same source code as Red Hat uses to build RHEL 5. One list of rebuild options is available at http://linuxmafia.com/faq/RedHat/rhel-forks.html.