xviii
is used for names of variables to which you assign values. Italic is also
used for comments in screen displays and examples, and to introduce
new terms.
courier
is used for system output (for example, screen displays, reports),
examples, and system prompts.
<Enter>, <Return> or <CR>
<CR> represents the carriage return or Enter key.
CTRL
represents the Control key. Execute control characters by pressing the
Ctrl key and the letter simultaneously, for example, Ctrl-d.