9.1. Conceptual Overview

vi is the classic screen-editing program for Unix. A number of enhanced versions exist, including nvi, vim, vile, and elvis. On GNU/Linux systems, the vi command is usually one of these programs (either a copy or a link). The Emacs editor, covered in Chapter 8, has several vi modes that allow you to use many of the same commands covered in this chapter.

The vi editor operates in two modes, command mode and insert mode. The dual mode makes vi an attractive editor for users who separate text entry from editing. For users who edit as they type, the modeless editing of emacs can be more comfortable. However, vim supports both ways of editing, through the insertmode option and the evim command for invoking vim.