Conventions Used in This Book
This book follows certain typographical conventions:
Italic is used to indicate URLs, filenames, directories, commands, options, system components (such as usernames), and to highlight comments in examples.
Used to show the contents of files or the output from commands.
Constant Width Bold
Used in examples and tables to show commands or other text that should be typed literally by the user.
Constant Width Italic
Used to show arguments and variables that should be replaced with user-supplied values.
Indicates a warning or caution.
A final word about syntax: in many cases, the space between an
option and its argument can be omitted. In other cases, the spacing (or
lack of spacing) must be followed strictly. For example,
n (no intervening
space) might be interpreted differently from -w
n. It’s important to notice the spacing used
in option syntax.