A Brief Intro to VI

Introduction

The vi editor and its clones elvis, vim, vile, nvi and several others are common on various versions of Unix and Linux; vi is routinely shipped with MacOS X and there are versions for Windows. The purpose of these pages is not to make you an expert, but rather, to get you started with a powerful but sometimes difficult to learn editor. There are many much longer tutorials that try to make you a vi expert; the vi lovers home page has a good index of these.

General Notes

Vi is designed with several interesting features that speed editing for experienced users but can be very frustrating for beginners:

• First, you never need to move your hands from the keyboard. Some variants of vi support use of the mouse for point-and-click editing, and all support use of the arrow keys, but editing is almost always faster if you keep your fingers over the keyboard's home row. In sum, vi is designed for the touch typist.

• Second, the original vi provided no on-line help and hardly any error messages. It just gave an audible beep in response to errors. Some modern versions do better, but few do very well. For all versions, what you see on the screen should match what is in your file; that might be enough feedback.

• Third, vi is a modal editor, operating in two main modes and several minor ones. Generally, it is in visual mode where single keystrokes operate on the text file; you can always return to this mode with the escape key. Text insert mode is entered by several command keys; in this mode, what you type becomes part of your file; to get out of this mode, use the escape key. The colon command takes you into command line mode, at which point, what you type appears on the command line at the bottom of the screen; your command will be executed when you hit return or enter.

Common Problems

• Vi users occasionally forget what mode they are in. For example, you hit j intending to move down a line, and instead, the letter j appears on the screen. The solution is to hit the escape key (ESC) in order to get back into visual mode. You won't do any harm if you hit the escape key more frequently than needed!

• The caps-lock key is very close to the escape key on some keyboards and the shift key on others. Unfortunately, vi users occasionally hit this key, and capitalized keystrokes in visual mode don't do the same thing as their lower-case equivalents. If you hit j intending to move down a line and, instead, two consecutive lines of text are joined (the capital J key does this), you've hit the caps-lock key. Unlock it and then try to repair the damage.

• Another rare problem occurs when vi gets stuck in command-line mode, with a colon on the left margin. This mode is a fossil remnant of a much older editor, qed, that is embedded in vi. To get back to the usual visual mode, type vi and then the return key.

Some Common VI Commands

Launching vi from the command line
	to edit file.txt	vi file.txt[CR]    ([CR] means return or enter)
Cursor movement
	left	h (may use arrow keys)
	down	j
	up	k
	right	l (or space)
	to next (previous) word	w (b)
	to start of next line	[CR]
	to line 55 of the file	:55[CR]
	to end of the file	:$[CR]
Search
	to next xxx in file	/xxx[CR]
	to previous xxx in file	?xxx[CR]
	match xpx or xqx or xrx	/x.x[CR]
	match xx or xyx or xyyyx	/xy*x[CR]
	match only xax or xbx	/x[ab]x[CR]
Undo
	undo last change	u
Save Changes and Exit
	save changes	:w[CR]
	save to temp.c	:w temp.c[CR]
	exit	:q[CR]
	force exit without saving	:q![CR]
Yank (copy) text into cut-paste buffer
	current word	yw
	current line	yy
	next 5 lines	5yy
Delete text (cut into cut-paste buffer)
	current character	x
	current word	dw
	to end of line	D
	current line	dd
	next 5 lines	5dd
	all lines containing xxx	:1,$g/xxx/d[CR]
Paste from cut-paste buffer
	after this character or line	p (lower case)
	before this character or line	P (upper case)
Insert text into file
	append xxx after cursor	axxx[ESC]    ([ESC] means the escape key)
	append xxx at end of this line	Axxx[ESC]
	insert xxx before cursor	ixxx[ESC]
	insert xxx at start of this line	Ixxx[ESC]
	from temp.txt after this line	:r temp.txt[CR]
Replace
	current character with x	rx
	next few characters with xxx	Rxxx[ESC]
	on this line, all xxx with yy	:s/xxx/yy/g[CR]
	globally, all xxx with yy	:1,$g/xxx/s//yy/g[CR]