Vi (text editor)

Vi (pronounced [ vi: aI ], but not [ vaI ] and never like the number 6) is a screen editor computer program written by Bill Joy for an early BSD release. The name comes from `Visual Interface', because its predecessor ex was a simple line editor. It became the de facto standard Unix editor and a nearly undisputed hacker favorite outside of MIT until the rise of Emacs after about 1984. It starts up faster than the bulkier versions of Emacs and uses less memory. It is much easier to fit a copy of vi on a rescue disk, and either vi or one of its clones can be found on nearly all installations of Unix.

Vi tends to frustrate new users to no end, because it is a modal editor. In the command mode, most of the keys are editing commands, such as moving the cursor, deleting text, and so on. In input mode, the user may type in text as expected, with the Escape key exiting this mode. Early versions of vi didn't give any indication as to which mode they were in, and it is typical of users to simply press the Escape key to ensure the editor is in command mode (it will beep if already in command mode). Current versions of vi indicate the mode on the status line or graphically. One advantage of issuing commands in a command mode is that multiple editing operations can be performed in a row with very simple keystrokes, without having to hold down the <Alt>, <Ctrl>, or other special modifier keys. For experienced users, this can lead to faster work.

Nevertheless it is still widely used by users of Unix variants (about half the respondents in a 1991 Usenet poll preferred it), and even Emacs fans often resort to it as a mail editor and for small editing jobs. When a "rescue floppy" is being built for restores following a hard drive crash, vi is often the editor chosen because it is compact enough to fit on a floppy, and because almost anyone performing rescue operations will probably be able to use it. See editor wars.