Conventions The following conventions are used in this document: bold is used for user input, as well as for the names of programs, directories, files, commands, and options and arguments to commands. italic is used for names of variables to which you assign values. Italic is also used for comments in screen displays and examples. courier is used for system output (e.g., screen displays, reports), examples, and system prompts. Enter represents the Enter or Return key. CTRL represents the Control key. Execute control characters by pressing the CTRL key and the letter simultaneously, e.g., CTRL-d.