Conventions Used in This Book

This book uses certain typographic styles in order to help you quickly identify important information and to avoid confusion over the meaning of words such as onscreen prompts. In particular, look for the following styles:

• Italicized text indicates key terms that are described or defined for the first time in a chapter. (Italics are also used for emphasis.)
• A monospaced font indicates the contents of configuration files, messages displayed at a text-mode Linux shell prompt, filenames, text-mode command names, and Internet URLs.
• Italicized monospaced text indicates a variable—information that differs from one system or command run to another, such as the name of a client computer or the name of a user’s data file.
• Bold monospaced text is information that you’re to type into the computer, usually at a Linux shell prompt. This text can also be italicized to indicate that you should substitute an appropriate value for your system. When isolated on their own lines, commands are preceded by nonbold monospaced $ or # command prompts, denoting regular user or system administrator use, respectively.

In addition to these text conventions, which can apply to individual words or to entire paragraphs, a few conventions highlight segments of text.

A margin note identifies additional information that may be relevant to the principal point of the accompanying paragraph, but that isn’t critical to its basic understanding. This could be a cross-reference to information in another chapter, an interesting but noncritical minor fact, or a warning about a rare pitfall of a procedure.

Many chapters of this book describe both GUI and text-mode methods of accomplishing tasks. Because you’re likely to be more familiar with GUI tools, most chapters begin with them; however, in most cases, Linux’s text-mode tools are more powerful. Furthermore, the Linux Essentials certification covers mainly text-mode tools. Therefore, be sure to learn the text-mode tools. As you gain proficiency with Linux, you’re likely to find yourself using the text-mode tools more often than the GUI tools because of the added flexibility that the text-mode tools provide. Furthermore, the GUI tools tend to vary a lot between distributions, whereas the text-mode tools vary much less.