Conventions (Linux in a Nutshell, 4th Edition)

0.2. Conventions

This desktop quick reference follows certain typographic conventions:

Bold: is used for commands, programs, and options. All terms shown in bold are typed literally.
Italic: is used to show arguments and variables that should be replaced with user-supplied values. Italic is also used to indicate filenames and directories and to highlight comments in examples.
Constant Width: is used to show the contents of files or the output from commands.
Constant Width Bold: is used in examples to show commands or other text that should be typed literally by the user.
Constant Width Italic: is used in examples to show text that should be replaced with user-supplied values.
%, $: are used in some examples as the tcsh shell prompt (%) and as the Bourne or bash shell prompt ($).
[ ]: 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 (e.g., the keyboard) is assumed. End with an end-of-file character.
EOF: indicates the end-of-file character (normally Ctrl-D).
|: is used in syntax descriptions to separate items for which only one alternative may be chosen at a time.

TIP: This icon indicates a note, which is an important aside to its nearby text.

WARNING: This icon indicates a warning.