how to use VI editor

The VI editor is a screen-based editor used by many Unix users. The VI editor has powerful features to aid programmers, but many beginning users avoid using VI because the different features overwhelm them. This tutorial is written to help beginning users get accustomed to using the VI editor, but also contains sections relevant to regular users of VI as well. Examples are provided, and the best way to learn is to try these examples, and think of your own examples as well... There's no better way than to experience things yourself.

Before You Begin

The VI editor uses the full screen, so it needs to know what kind of terminal you have. When you log in, wiliki should ask you what terminal you have. The prompt looks like this:

	TERM = (vt100)

If you know your terminal is a vt100 (or an emulator that can do vt100), just hit return for the terminal type when you log in. If you have an hp terminal, type "hp" for the terminal type and hit return. If you are not sure what kind of terminal you have, ask a lab monitor, or have someone help you set the correct terminal type.

If you make an error when you log in and type the wrong terminal type, don't panic and log out. You can type the following commands to fix the settings:

First, tell your shell what type of terminal you have. (If you're not sure what your shell is, type this command to see what shell you have: echo $SHELL.) For the examples given, the terminal type is "vt100". Substitute it with whatever terminal type you have. For C shell (/bin/csh), the command is this:


        set term=vt100

For Bourne Shell (/bin/sh) or Korn Shell (/bin/ksh), the commands are the following:


        export TERM

        TERM=vt100

Next, reset your terminal with this command:


        tset

Now that the terminal type is (hopefully) correctly set, you are ready to get started with VI.

Starting the VI Editor

The VI editor lets a user create new files or edit existing files. The command to start the VI editor is vi, followed by the filename. For example to edit a file called temporary, you would type vi temporary and then return. You can start VI without a filename, but when you want to save your work, you will have to tell VI which filename to save it into later.

When you start VI for the first time, you will see a screen filled with tildes (A tilde looks like this: ~) on the left side of the screen. Any blank lines beyond the end of the file are shown this way. At the bottom of your screen, the filename should be shown, if you specified an existing file, and the size of the file will be shown as well, like this:

"filename" 21 lines, 385 characters

"newfile" [New file]

Getting Out of VI

Now that you know how to get into VI, it would be a good idea to know how to get out of it. The VI editor has two modes and in order to get out of VI, you have to be in command mode. Hit the key labeled "Escape" or "Esc" (If your terminal does not have such a key, then try ^[, or control-[.) to get into command mode. If you were already in the command mode when you hit "Escape", don't worry. It might beep, but you will still be in the command mode.

The command to quit out of VI is :q. Once in command mode, type colon, and 'q', followed by return. If your file has been modified in any way, the editor will warn you of this, and not let you quit. To ignore this message, the command to quit out of VI without saving is :q!. This lets you exit VI without saving any of the changes.

Of course, normally in an editor, you would want to save the changes you have made. The command to save the contents of the editor is