Certified Engineer

RedhatIn this article we will talk about RHCE prerequisites. For the RHCE and RHCT exams, the skills outlined in this article 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.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.

Basic Hardware Knowledge

The architecture of a PC defines the components that it uses as well as the way that they are connected. In other words, the Intel-based architecture describes much more than just the CPU. It includes standards for other hardware such as the hard drive, the network card, the keyboard, the graphics adapter, and more. All software is written for a specific computer architecture, such as the Intel-based 32-bit architecture. Even when a manufacturer creates a device for the Intel platform, it may not work with Linux. Therefore, it's important to know the basic architecture of an Intel-based computer. While it is important to know how Linux interacts with your hardware, the RHCE and RHCT exams are not
hardware exams.

Basic Linux Knowledge

Linux and Unix are managed through a series of text files. Linux administrators do not normally use graphical editors to manage these configuration files. Editors such as WordPerfect, OpenOffice.org Writer, and yes, even Microsoft Word normally save files in a binary format that Linux can't read. Popular text editors for Linux configuration files include nano, pico, joe, and vi. If you already know one of these editors, feel free to skip this section. If you have to rescue an RHEL 5 system (as may be required during the exam), you'll have access to these editors when booting your system from RHEL 5 rescue media. While emacs may be the most popular and flexible text editor in the world of Linux, I believe every
administrator needs at least a basic knowledge of vi, which may help you save a broken system. If you ever have to restore a critical configuration file using an emergency boot floppy, vi is probably the only editor that you'll have available.

Linux Filesystem Hierarchy and Structure

Everything in Linux can be reduced to a file. Partitions are associated with filesystem device nodes such as /dev/hda1. Hardware components are associated with node files such as /dev/dvd. Detected devices are documented as files in the /proc directory. The Filesystem Hierarchy Standard (FHS) is the official way to organize files in Unix and Linux directories. As with the other sections, this introduction provides only the most basic overview of the FHS. More information is available from the official FHS homepage at www.pathname.com/fhs.

Basic File Operations and Manipulation

Two basic groups of commands are used to manage Linux files. One group helps you get around Linux files and directories. The other group actually does something creative with the files. Remember that in any Linux file operation, you can take advantage of the HISTORY (this is capitalized because it's a standard environment variable) of previous commands, as well as the characteristics of command completion, which allow you to use the TAB key almost as a wildcard to complete a command or a filename or give you the options available in terms of the absolute path.
Almost all Linux commands include switches, options that allow you to do more. If you're less familiar with any of these commands, use their man pages. Study the switches. Try them out! Only with practice, practice, and more practice can you really understand the power behind some of these commands.

Posted on: 11/12/2009

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