Vi is a visual text editor developed for UNIX systems and ported to a variety of other computing platforms. It is still one of the most-used ways people compose files on a UNIX system.
A visual editor presents a full screen window containing the contents of a file. The cursor, which indicates the current insertion point, is always visible on the vi screen. Vi is designed so you only need the normal typewriter keys (plus the ESC key). If you are a touch-typist you will find that, with some practice, you can do all the tasks needed to edit a file without moving your hands far from the touch-typing home keys. The arrow keys, although not needed, are frequently easier to use to move the insertion point around the file.
Since vi only uses the standard typewriter keys, it uses two modes:
It is important to remember that vi only uses the keyboard keys, and that the program is cursor-based. That is, if your terminal window is on a system with a mouse, the mouse will not help you move the cursor within the vi window. You can, however, use the mouse to select text for copying and pasting; so long as you are in insert mode when you want to paste the text into the file.
The vi program is available on the central UNIX systems (e.g., Copland, Strauss, Mahler), within the Terminal window on MacOS X systems in computing labs, and on other UNIX systems on campus.
Since MacOS computers run a version of UNIX, vi is already available in the Apple Terminal program. If you have a Windows computer and wish to use vi as your text editor, we recommend installing an extended version of vi called vim, which gives you all the features of the UNIX keyboard as well as a screen-oriented interface. You can get vim from the vim web site.Vim supports some enhanced features, such as some uses of a Windows system's mouse.