Chapter 1
Starting with Linux Shells

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In This Chapter

1. What is Linux?
2. Parts of the Linux kernel
3. Exploring the Linux desktop
4. Visiting Linux distributions

Before you can dive into working with the Linux command line and shells, you should first understand what Linux is, where it came from, and how it works. This chapter walks you through what Linux is and explains where the shell and command line fit in the overall Linux picture.

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What Is Linux?

If you've never worked with Linux before, you may be confused about why so many different versions are available. I'm sure you have been confused by various terms such as distribution, LiveCD, and GNU when looking at Linux packages. Wading through the world of Linux for the first time can be a tricky experience. This chapter takes some of the mystery out of the Linux system before you start working on commands and scripts.

First, four main parts make up a Linux system:

• The Linux kernel
• The GNU utilities
• A graphical desktop environment
• Application software

Each of these parts has a specific job in the Linux system. No part is very useful by itself. Figure 1.1 shows a basic diagram of how the parts fit together to create the overall Linux system.

Figure 1.1 The Linux system

This section describes these four main parts in detail and gives you an overview of how they work together to create a complete Linux system.

Looking into the Linux Kernel

The core of...

Linux Distributions

Now that you have seen the four main components required for a complete Linux system, you may be wondering how you are going to get them all put together to make a Linux system. Fortunately, other people have already done that for you.

A complete Linux system package is called a distribution. Many different Linux distributions are available to meet just about any computing requirement you could have. Most distributions are customized for a specific user group, such as business users, multimedia enthusiasts, software developers, or average home users. Each customized distribution includes the software packages required to support specialized functions, such as audio- and video-editing software for multimedia enthusiasts, or compilers and integrated development environments (IDEs) for software developers.

The different Linux distributions are often divided into three categories:

• Full core Linux distributions
• Specialized distributions
• LiveCD test distributions

The following...

Summary

This chapter discussed the Linux system and the basics of how it works. The Linux kernel is the core of the system, controlling how memory, programs, and hardware all interact with one another. The GNU utilities are also an important piece in the Linux system. The Linux shell, which is the main focus of this book, is part of the GNU core utilities. The chapter also discussed the final piece of a Linux system, the Linux desktop environment. Things have changed over the years, and Linux now supports several graphical desktop environments.

The chapter also discussed the various Linux distributions. A Linux distribution bundles the various parts of a Linux system into a simple package that you can easily install on your PC. The Linux distribution world consists of full-blown Linux distributions that include just about every application imaginable, as well as specialized Linux distributions that include applications focused only on a special function. The Linux LiveCD craze has created...