Using the VI Editor

This document is intended to be an introduction to the use of the VI editor. It is by no means complete.

The VI editor is available on the Unix computers at Niagara at the current writing. In the discussion below, we use the "$" as a generic representative of the operating system's prompt message. Some items will be underlined in order to stress what the user must type.

ENTERING VI is done via a command of the form
```
	$ vi filename
```
where "filename" is the name of the file you wish to edit. VI may be entered in this way whether the file is old or new. Regardless, you enter VI in "command mode" (see the item on MODES, below).
CASE: note that VI commands are case-sensitive -- for example, the command R is different from the command r.
MODES AND MODE CHANGES. The VI editor has two "modes" of operation: text entry mode and command mode. Text entry mode is used for the insertion of new text into the file being edited. Command mode is used for all other editing operations.

NOTE: VI is an editor, not a word processor. Although editors and word processors are functionally similar, one major difference is that editors require you to strike the RETURN/ENTER key at the end of a line when you enter text in order to create a new line in the computer's memory. This is because editors are generally used to write programs, a situation in which we insist on new lines more frequently than when we write letters to Mom and Dad.
- CHANGING FROM COMMAND TO TEXT ENTRY MODE may be done in a variety of ways. All begin with the cursor at (or near) the point in the file where new text is to be inserted.
```
Command  Explanation
i       (insert) start at the position of the cursor
a       (after)  start at the position following that of
	the cursor
O (oh)  start a new line above the position of the cursor
o       start a new line below the position of the cursor
R       (Replace) enter new text as strikeover for the
	current line -- however, any text you enter
	past the current end-of-line (i.e., by 
	striking the return key) is entered as insertion,
	rather than replacement
```
- CHANGING FROM TEXT ENTRY TO COMMAND MODE is done by striking the Escape key.

CURSOR MOVEMENT COMMANDS: Note that most of these may be "multiplied" to obtain a repeating effect. For example, the command

moves the cursor down by one line; the command

15j

moves the cursor down by 15 lines. Except as noted, only the unmultiplied are given in the table below:

Command   Explanation
 j	  move down 1 line
 k	  move up 1 line
return	  move to start of next line
 h        move left 1 character
backsp      "    "  1     "
 l        move right 1 character
space       "    "   1     "
 w        (word) move right 1 word
 b        (back) move left 1 word
 e        (end) move to end of current or next word
 $        move to right end of current line
 0 (zero) move to left end of current line
 H	  move to top of current screen
 L        move to bottom of current screen
ctrl-u    (up) move up half a screen (12 lines)
ctrl-d    (down) move down half a screen
ctrl-f    (forward) move forward 1 screen
ctrl-b    (back) move back 1 screen
 G        go to end (last line) of file (unmultipliable --
       	     see next command)
nG        go to line n, e.g.,  250G  moves cursor to line 250
/string   go (forward) to next occurrence of string.  The
	     search wraps circularly past the end of the
	     file, if necessary, to search the earlier part
	     of the file for the string.

	  Example:  /Niagara
		    moves the cursor forward to "Niagara"

?string   go (backward) to previous occurrence of string.
	     The search wraps circularly past the start of
	     the file, if necessary, to search the later part
	     of the file for the string.

	  Example:  ?University
		    moves the cursor backward to "University"

 n	  (next) go the next (forward or backward) occurrence
	     of the string searched for by the last  /  or  ?
	     command, respectively

DELETE COMMANDS -- as with the cursor movement commands, most of these may be multiplied to obtain a repeating effect.

Command  Explanation
 x       delete current character
 dw	 (delete word) delete from current character
	    through end of current "word" including
	    trailing blank(s)
 dd      delete current line
 dG      delete the part of the file starting with
	    the current line
 r       replace current character with next character
	    typed.  For example, if the cursor is at the
            "h" of the when the user types ri, "h" is
            replaced by "i" so that the word becomes tie.

COPYING TEXT (copy-and-paste):
- To copy one or more lines, you may do the following. Move the cursor to the first line you wish to copy. Use Y (yank) for one line, or nY (n a positive integer, e.g., 8Y for 8 lines) to copy the line(s) to a temporary buffer. Move the cursor to the line in front of which you wish to copy the text. Give the command P (for point).
- If you're using Telnet in a Windows environment, you may
  -- drag the cursor over a block of text (not necessarily whole lines);
  -- click (on the Telnet menu) Edit, Copy;
  -- move the cursor to the desired destination;
  -- give the appropriate VI insert or replace command (for example, i, a, O, o, or R);
  -- click (on the Telnet menu) Edit, Paste.
MOVING TEXT (cut-and-paste): Substitute dd for Y in the description of copying lines, above.

NOTE: the P command may be used to insert whatever was last deleted or copied to the temporary buffer. Above, we illustrated copying and moving lines; however, e.g., if 5dw is followed by a cursor movement and then P, the user has moved 5 words.

FILE OPERATIONS:

     Command      Explanation
     :w	          (write) save to default filename without exiting VI
     :w filename  save to file named without exiting VI
     :r filename  (read) import named file, inserting it beginning at
		     line below current cursor location
     ZZ	          save to default filename and exit VI to the
                     operating system
     :q	          quit VI without saving (use  :q!  if changes you
                     don't wish to save have been made in the file)

MISCELLANEOUS COMMANDS:

      Command		Explanation
        ctrl-g    	get line number of current line in file
	J		join next line to current line,
                           combining 2 lines into 1
	u               undo previous operation

Additional commands are discussed in this document.

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