The following typographical conventions are used in this book:
Indicates new terms, URLs, email addresses, filenames, file extensions, pathnames, directories, and Unix utilities.
Indicates commands, options, parameters, and arguments that must be substituted into commands.
Constant width bold
Shows commands or other text that should be typed literally by the user . Also used for emphasis in code.
Shows text that should be replaced with user-supplied values.
Indicates optional keywords and arguments.
Signifies either choice-1 or choice-2.