vi

Description

The program vi is a visual text editor for Unix. It is the de facto standard visual editor for Unix systems. A visual editor presents a full screen representation of the contents of the file in a terminal window called the screen. On the screen there is always a cursor which indicates the current insertion point. The vi editor 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 editor modes to know which action is assigned to each key. The two primary modes are command mode and insert mode.

You must always remember which mode you are in; thus vi takes some practice to become proficient.

It is important to remember that vi only uses the keyboard keys, and everything is done in reference to the cursor. If your terminal window is on a system having a a mouse, then the mouse has no direct relationship to the vi operation. (You can use the mouse to select text and paste it from the clipboard onto your vi screen as long as you are currently in insert mode.)

Where to Find vi

• Where Can I Use vi on Campus?

  The vi program is available on Strauss and Mahler and most other Unix systems. To edit a file, type the Unix command:

  vi fileName

  If fileName does not exist, vi will create a new empty file having that name.

• How Can I Obtain vi for my Personal Computer?

  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 online web site. You will also get enhanced features allowing your to use a mouse in an MS Windows environment.

Instructions for vi

• How Do I run vi on Strauss or Mahler?

  Use the vi Unix command. To edit a file named "program.c", for example, type the command

  vi program.c

  If program.c does not exist, vi will create the file.

  You will get a screen that displays the contents of your file.

  #include "theta.h"
  
  int main() {
          int i;
          printf("  i   theta0 theta1 inv(theta0,theta1)\n");
          for (i=1; i<=32; i++) {
                  printf("%3d %6d %6d ",i,theta0(i),theta1(i));
                  printf("%13d\n",invTheta(theta0(i),theta1(i)));
          }
  }
  ~
  ~
  ~
  ~
  ~
  ~
  ~
  ~
  ~
  "program.c" 10 lines, 236 characters

  The lines with start with ~ are placeholders and indicate that the line is empty.

• How do I move around the vi screen

  When you first start vi, you begin in command mode. The command mode keystrokes let you move around the screen. These one-letter commands are also used in many other Unix commands, so it is worth learning them. The commands are case-sensitive: an upper-case X has a different action than a lower-case x.

  h j k l

  Character motion commands: These positional commands move the cursor one character left, up, down, and right, respectively. You can use the arrow keys instead, if you prefer.

  e b

  Word motion commands: Moves to the end of the next word or the beginning of the previous word. Punctuation marks count as single-character words.

  E B

  Word motion commands. Same as the lower-case commands except the punctuation marks are now considered part of the word. These commands move forward and backward to the next white space.

  ( )

  Sentence motion commands. Move forward and backward, sentence by sentence.

  { }

  Paragraph motion commands. Move forward and backward, paragraph by paragraph.

  /string
  ?string

  Context motion commands. These move forward and backward to the next occurrence of the string you typed. This is a useful way to move quickly to the place you want.

  All of these motion commands will scroll the window, if needed, so the cursor remains visible on the screen. Thus you can move to any point in the file with these commands.

• How do I modify the file in vi?

  When you start vi with the vi command, you begin in command mode. All the keys you type will be interpreted as commands, and they will not appear in the document. To insert text you must change to "insert mode" by typing i (or a). The ESC key returns you to command mode.

  There are many text-modification commands to delete, replace, modify, and insert text in the document. These commands are described in the tutorials listed in the More Help section below.

• How to I quit from a vi screen

  To exit vi and save the file, type the sequence :wq or ZZ. (If the characters :wq or ZZ appear in the text, it is because you are in "insert mode", not "command mode." You must type the ESC key to exit insert mode and re-enter command mode. Then delete the unwanted characters and retype the sequence :wq or ZZ.

  To exit without saving the file, just type the sequence :q!.

• Are there any environment variables or setup files I need for vi?

  No. The vi program needs very little to run; it does not even need the arrow keys to work properly. However, there is a setup file and some things you may want to do to make what you learn using vi more broadly useful.

  .exrc

  This is the vi run control file (setup file). If you find some commands you always want executed every time you start vi, this is the file to modify. For example, to change your tab stops to 4 instead of the default 8, put the following line in your .exrc file:

  set ts=4
  

  Advanced users can set function keys in the .exrc file to have macros available while using vi.

  VISUAL

  This is the environment variable used by many Unix programs. It indicates your preferred visual editor (vi is the default). To make sure you get vi, put the following line in your .cshrc file.

  setenv VISUAL vi
  

  bindkey -v

  The tcsh has a built-in editor you can use to edit the Unix command you are currently typing or previously typed commands before you submit the command with a RETURN. You can tell tcsh to use the vi key bindings you have learned in using vi with the shell command bindkey -v. If you want this behavior for all shells put this line in your .cshrc file:

  if ?$tcsh bindkey -v
  

  Note: We recommend putting all your shell run-control commands in .cshrc, the csh run-control file. For commands that work only in the tcsh, prepend if ?$tsch in front of those commands, as illustrated above.

More Help

There are many thousands of web pages describing the use of vi. Here are a small sample:

• vi tipsheet is a beginner's tipsheet describing the basics of modifying files and text manipulation. It was written in 1997, but vi has not changed since then.
• Mastering the VI editor from the University of Hawaii at Manoa College of Engineering, is a good next step. It is much more complete list of features.
• An Introduction to Display Editing with Vi is a classic written by the original author of vi, Bill Joy, along with Mark Horton. Even though it is quite complete, it is accessible to beginners.
• vi reference by Maarten Letmaath is a "compact and usable listing of command and insert mode keys, ex commands and options." It is reference material and not a tutorial.
• Unix Lovers Home gage is a collection of links to more information on vi as well as its variants.
• Vim Documentation is a comprehensive collection of documentaion on Vim. We recommend vim for MS Windows users wanting to use vi. Since Vim is a enhancement to Vi, much of the documentation is still useful to vi users.
• The Cult of vi is an unabashed advocacy page for vi (and emacs bashing). Here is the place to go to transform yourself so "editing power crackles through your fingertips."

If you need help quickly, you may call the IT Help Center at 831-6000 between 8 a.m. and 5 p.m., Monday through Friday. Or, you can submit a question through e-mail.