Items appearing in this book are sometimes given a special appearance to set them apart from the regular text. Here's how they look:
Used for commands, email addresses, URIs, filenames, emphasized text, first references to terms, and citations of books and articles.
Used for literals, constant values, code listings, and XML markup.
Constant width italic
Used for replaceable parameter and variable names.
Constant width bold
Used to highlight the portion of a code listing being discussed.