Items appearing in this book are sometimes given a special appearance to set them apart from the regular text. Here's how they look:

Italic: Used for commands, email addresses, URIs, filenames, emphasized text, first references to terms, and citations of books and articles.
Constant width: 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.

These icons signify a tip, suggestion, or general note.

These icons indicate a warning or caution.