This book follows the typographic conventions that are outlined below:
Used for directory names, commands, program names, functions, variables, and options. All terms shown in constant width are typed literally. It is also used to show the contents of files or the output from commands.
Constant width italic
Used in syntax and command summaries to show generic text; these should be replaced with user-supplied values.
Constant width bold
Used in examples to show text that should be typed literally by the user.
Used to show generic arguments and options; these should be replaced with user-supplied values. Italic is also used to indicate URLs, macro package names, filenames, comments in examples, and the first mention of terms.
Used in some examples as the Bash, Bourne or Korn shell prompt.
Indicates the “manpage” for program in section N of the online manual. For example, echo (1) means the entry for the
Surround optional elements in a description of syntax. (The brackets themselves should never be typed.) Note that many commands show the argument [files]. If a filename is omitted, standard input (usually the keyboard) is assumed. End keyboard input with an end-of-file character.
indicates a “control character,” typed by holding down the Control key and the x key for any key x.
Used in syntax descriptions to separate items for which only one alternative may be chosen at a time.