The following typographical conventions are used in the text of this book:
Italic
Indicates emphasis, new terms, URLs, email addresses, filenames, paths, and Unix utilities.
Constant-width regular
Indicates commands, variables, attributes, functions, classes, namespaces, methods, modules, values, the contents of files, the output from commands, and code examples that break recommended practices.
Constant-width bold
Indicates commands and other text that should be typed literally by the user, and code examples that demonstrate recommended practices.
Constant-width italic
Indicates text that should be replaced with user-supplied values and comments within code examples.