The following typographical conventions are used in this book:
Indicates new terms, URLs, email addresses, filenames, file extensions, path names, directories, and Unix utilities.
Constant width
Indicates commands, options, switches, variables, attributes, keys, functions, types, classes, namespaces, methods, modules, properties, parameters, values, objects, events, event handlers, XMLtags, HTMLtags, the contents of files, or the output from commands.
Constant width bold
Shows commands or other text that should be typed literally by the user. Also used for emphasis in code samples.
Constant width italic
Shows text that should be replaced with user-supplied values.
Indicates a reference to the bibliography.