Getting Started with vi

by Donald Hyatt

What is vi?

The fundamental UNIX editor is called vi. It is a primitive editor, but it will be found on every UNIX system, and works well when logging in remotely from home. There are just a few commands that one needs to learn at first, and they will be sufficient to write simple files. For more advanced features, consult some of the handouts and books available in the CS lab.

The Basics of vi

There are essentially three Modes in vi, the Insert Mode where one is typing in new text, the Edit Mode where one is modifying text that is already there, and the Command Mode where one is interacting with the operating system with actions like reading and writing files.

Most of the commands require just a simple letter or two, but be careful to note that vi is case sensitive, and capital letters do different things from lower case letters. It is not necessary to learn all of these commands, but eventually they will become second nature. The basic operations needed to create a file are related to each of those modes, so let's look at them separately.

INSERT Mode - For adding text to a file
The three most common ways to enter the Insert Mode are:

Letter	Action
i	Starts inserting in front of the current cursor position
I	Starts adding at the front of the line
a	Starts adding after the cursor
A	Starts adding at the end of the line
o	Starts opening a new line underneath the cursor
O	Starts opening a line above the cursor.
<Esc>	Gets out of Insert Mode

EDIT Mode

Letter	Simple Cursor Movement
h	Moves cursor left one space	Note: the Arrow keys do work locally, but sometimes mess up over a network.
j	Moves cursor down one line
k	Moves cursor up one line
l	Moves cursor right one space
Fast Cursor Movement
w	Moves the cursor a full word at a time to the right
b	Moves the cursor back to the left a word at a time
^	Moves the cursor to the front of a line
$	Moves the cursor to the end of a line
<ctrl>f	Moves the cursor forward a full page of text at a time
<ctrl>b	Moves the cursor backward a full page of text at a time
Modifying Text
x	Deletes the character under the cursor
dd	Deletes the line where the cursor is located (type d twice!)
n dd	Delete n consecutive lines ( n is an integer)
r	Replaces the character under the cursor with the next thing typed
J	Joins current line with the one below (Capital J!)
u	Undoes the last edit operation
<ctrl> r	Redo (Undoes the last undo operation)
Cut and Paste Operations
yy	Copies or yanks a line ( 5yy yanks 5 lines)
p	Puts the yanked text on the line below the cursor (lower case p)
P	Puts the yanked text above the current line (capital P)
*Note*: If vi is already in the input mode, text from that or another window may be highlited using the left mouse button, and copied into place by pressing the middle mouse button.

COMMAND Mode - For interacting with the operating system.
To enter the Command Mode, a colon " : " must precede the actual command.

Letter	Action
: r <file>	reads a file from disk into the vi editor
: w <file>	writes current file to disk
: wq	writes the file and quits vi
: q!	quits without writing (useful if you've messed up!)