Conventions Used in This Book

Throughout this book certain stylistic conventions are followed. Once you are accustomed to them, you will distinguish between comments, commands you need to type, values you need to supply, and so forth.

In some cases, the typeface of the terms in the main text and in code examples will be different. The details of what the different styles (italic, boldface, etc.) mean are described in the following sections.

Programming Conventions

In command prompts shown for Unix systems, prompts that begin with # indicate that you need to be logged in as the superuser (root username); if the prompt begins with $, then the command can be typed by any user.

Typesetting Conventions

The following typographical conventions are used in this book:

Italic

Indicates new terms, URLs, email addresses, filenames, file extensions, pathnames, directories, usernames, group names, module names, CGI script names, programs, and Unix utilities

Constant width

Indicates commands, options, switches, variables, functions, methods, HTML tags, HTTP headers, status codes, MIME content types, directives in configuration files, the contents of files, code within body text, and the output from commands

Constant width bold

Shows commands or other text that should be typed literally by the user

Constant width italic

Shows text that should be replaced with user-supplied values

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