Fundamentals of VI editor

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Three basic modes of operation :
- command mode
- edit mode
- last line mode

Command Mode
The command mode is the default mode for the vi editor. In this mode, you can perform commands to delete, change, copy, and move text. You can also position the cursor, search for text strings, and exit the vi editor.

Edit Mode
You can enter text into a file in the edit mode. The vi editor interprets everything you type in the edit mode as text. To enter the edit mode, perform the commands:

i - Inserts text before the cursor
o - Opens a new blank line below the cursor
a - Appends text after the cursor

Last Line Mode
You can use advanced editing commands in the last line mode. To access the last line mode, enter a colon (:) while in the command mode. The colon places your cursor at the bottom line of the screen.

Switching Between the Command and Edit Modes

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The default mode for the vi editor is the command mode. When you perform an i, o, or a command, the vi editor switches to the edit mode. After editing a file, press Escape to return the vi editor to the command mode. When in the command mode, you can save the file and quit the vi editor.

The following example shows how to switch modes in the vi editor:
1. Perform the vi filename command to create a file. You are automatically in the command mode.
2. Type the i command to insert text. The i command switches the vi editor to the edit mode.
3. Press Escape to return to the command mode.
4. Perform the :wq command to save the file and exit the vi editor.

TABLE OF CONTENTS

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1. Using the VI editor
2. Inserting and appending text
3. Moving cursor within VI editor
4. Editing files by using VI editing commands
5. Using text changing commands
6. Using the text replacing commands
7. Using the text copying and text pasting commands
8. Using the file save and quit commands
9. Customizing the VI session


Using the vi editor

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vi filename
vi options filename

To recover a file :
vi -r filename

To open file in read-only mode :
vi -R filename
or
view filename


Inserting and appending text

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Input Commands for the vi Editor

Command	Function
a	Appends text after the cursor
A	Appends text at the end of the line
i	Inserts text before the cursor
I	Inserts text at the beginning of the line
o	Opens a new line below the cursor
O	Opens a new line above the cursor
:r filename	Inserts text from another file into the current file

Moving cursor within VI editor

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Key Sequences for the vi Editor

Key Sequence	Cursor Movement
h, left arrow, or Backspace	Left one character
j or down arrow	Down one line
k or up arrow	Up one line
l, right arrow, or space bar	Right (forward) one character
w	Forward one word
b	Back one word
e	To the end of the current word
$	To the end of the line
0 (zero)	To the beginning of the line
^	To the first non-white space character on the line
Return	Down to the beginning of the next line
G	Goes to the last line of the file
1G	Goes to the first line of the file
:n	Goes to Line n
nG	Goes to Line n
Control-F	Pages forward one screen
Control-D	Scrolls down one-half screen
Control-B	Pages back one screen
Control-U	Scrolls up one-half screen
Control-L	Refreshes the screen
Control-G	Displays current buffer information

Editing files by using VI editing commands

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Text-Deletion Commands for the vi Editor

Command	Function
R	Overwrites or replaces characters on the line at and to the right of the cursor. To terminate this operation, press Escape.
C	Changes or overwrites characters from cursor to the end of the line.
s	Substitutes a string for a character at the cursor.
x	Deletes a character at the cursor.
dw	Deletes a word or part of the word to the right of the cursor.
dd	Deletes the line containing the cursor.
D	Deletes the line from the cursor to the right end of the line.
:n,nd	Deletes Lines n -n (for example, :5,10d deletes Lines 5-10).

Using text changing commands

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Edit Commands for the vi Editor

Command	Function
cw	Changes or overwrites characters at the cursor location to the end of that word
r	Replaces the character at the cursor with one other character
J	Joins the current line and the line below
xp	Transposes the character at the cursor and the character to the right of the cursor
~	Changes the case of the letter, either uppercase or lowercase, at the cursor
u	Undoes the previous command
U	Undoes all changes to the current line
.	Repeats the previous command

Using the text replacing commands

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Edit Commands for the vi Editor

Command	Function
cw	Changes or overwrites characters at the cursor location to the end of that word
r	Replaces the character at the cursor with one other character
J	Joins the current line and the line below
xp	Transposes the character at the cursor and the character to the right of the cursor
~	Changes the case of the letter, either uppercase or lowercase, at the cursor
u	Undoes the previous command
U	Undoes all changes to the current line
.	Repeats the previous command

Using the text copying and text pasting commands

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Copy and Paste Commands

Command	Function
yy	Yanks a copy of a line
p	Puts yanked or deleted text under the line containing the cursor
P	Puts yanked or deleted text before the line containing the cursor

Additional Copy and Paste Commands

Command	Function
:n,n co n	Copies Lines n -n and puts them after Line n. For example, :1,3 co 5 copies Lines 1-3 and puts them after Line 5.
:n,n m n	Moves Lines n -n to Line n. For example, :4,6 m 8 moves Lines 4-6 to Line 8. Line 6 becomes Line 8. Line 5 becomes Line 7. Line 4 becomes Line 6.

Using the file save and quit commands

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Save and Quit Commands

Command	Function
:w	Saves the file with changes by writing to the disk
:w new_filename	Writes the contents of the buffer to new_filename
:wq	Saves the file with changes and quits the vi editor
:x	Saves the file with changes and quits the vi editor
ZZ	Saves the file with changes and quits the vi editor
:q!	Quits without saving changes

Customizing the VI session

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Edit Session Customization Commands

Command	Function
:set nu	Shows line numbers
:set nonu	Hides line numbers
:set ic	Instructs searches to ignore case
:set noic	Instructs searches to be case sensitive
:set list	Displays invisible characters, such as ^I for a Tab and $ for end-of-line characters
:set nolist	Turns off the display of invisible characters
:set showmode	Displays the current mode of operation
:set noshowmode	Turns off the mode of operation display
:set	Displays all the vi variables that are set
:set all	Displays all set vi variables and their current values

To create an automatic customization for all of your vi sessions, complete the following steps:

1. Create a file in your home directory named .exrc.
2. Enter the set variables into the .exrc file.
3. Enter set variable without the preceding colon.
4. Perform one command on one line.

The vi editor reads the .exrc file located in your home directory each time you open a vi session, regardless of your current working directory.

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