The following typographic conventions are used in this book:
Italic
Used for file and directory names, email addresses, and URLs, as well
as for new terms where they are defined.
Constant width
Used for code listings and for keywords, variables, function names,
command options, parameters, and bits of HTML source where they
appear in the text.
Constant width bold
Used to highlight key fragments of larger code examples, or to show
the output of a piece of code.
Constant width italic
Used as a general placeholder to indicate terms that should be
replaced by actual values in your own programs.