Vi Text Editor

Introduction to the Vi Editor

• Before vi, UNIX used a line editor that allowed editing one line at a time.
• vi (Visual Editor) was created by Bill Joy in 1976.
• It is the default editor in Linux/UNIX systems and is case-sensitive.
• vim (Vi IMproved) is an advanced version of vi.
• Used for creating, editing, or viewing text files.
• Not a text formatter (unlike MS Word); no margins or formatting controls.

Characteristics of Vi

• Powerful and universally available on UNIX systems.
• Harder to learn for new users, especially Windows users.
• Allows movement and modification anywhere in a file.
• Case-sensitive commands.

Starting Vi

vi filename

• Creates filename if it doesn't exist, otherwise opens it.
• Opens in Command Mode by default.

Modes of Operation

Vi has three modes:

1. Command Mode – Default mode for navigation and commands.
2. Insert Mode – Used to type and edit text.
3. Last Line Mode (Escape Mode) – Used to save, quit, or execute commands.

Command Mode

• Activated by pressing Esc.
• Keystrokes are interpreted as commands (not shown on screen).
• Used for navigation, deletion, copying, and pasting text.
• Pressing Esc again makes vi beep or flash if already in command mode.

Insert Mode

• Entered from Command Mode by pressing i.
• Allows text input and editing.
• Exit by pressing Esc to return to Command Mode.

Example

vi vifile
i
This file is being created using the vi editor.
<Esc>

Last Line Mode (Escape Mode)

• Invoked by typing a colon : in Command Mode.
• Cursor moves to the bottom for entering commands.

Common Commands

Command	Action
:q	Quit
:q!	Quit without saving
:w	Save file
:w!	Force save file
:w filename	Save file as filename
:wq or :x	Save and quit
ZZ	Save and quit

Input Mode Shortcuts

Command	Action
i	Insert before cursor
I	Insert at start of line
a	Append after cursor
A	Append at end of line
o	Open new line below
O	Open new line above
r	Replace one character
R	Overwrite text

Navigation and Cursor Movement

Basic Movement

Command	Action
h	Move left
j	Move down
k	Move up
l	Move right

Word Navigation

Command	Action
w	Move to next word
b	Move to previous word
e	Move to end of word
n w	Move forward n words
dw	Delete one word
yw	Copy one word
n dw	Delete n words

Line Navigation

Command	Action
0, |, or ^	Move to start of line
$	Move to end of line
30 |	Move to column 30

Scrolling

Command	Action
Ctrl+f	Scroll one page forward
Ctrl+b	Scroll one page backward
Ctrl+d	Scroll half page forward
Ctrl+u	Scroll half page backward
10 Ctrl+f	Scroll 10 pages forward

Absolute Movement

Command	Action
Ctrl+g	Show current line number
G	Go to end of file
1G or gg	Go to first line
nG	Go to line n (e.g., 40G)

Cut, Copy, and Paste

Commands

Command	Action
dd	Cut (delete) current line
yy	Copy (yank) current line
p	Paste below cursor
P	Paste above cursor
n dd	Delete n lines
n yy	Copy n lines

Deleting Text

Command	Action
x	Delete current character
X	Delete previous character
xp	Swap two characters
dw	Delete to end of word
d$ or D	Delete to end of line
d0	Delete to start of line
dd	Delete whole line
:20,40d	Delete lines 20 to 40
dG	Delete to end of file

Editing and Joining Lines

Command	Action
J	Join current and next line
4J	Join 4 lines
yyp	Duplicate current line
ddp	Swap two lines

Undo and Repeat

Command	Action
u	Undo last change
ctrl+r	Redo last change
U	Undo all changes on current line
.	Repeat last command

Searching for a Pattern

Search Commands

Command	Action
/string	Search forward
?string	Search backward
n	Go to next match (same direction)
N	Go to previous match (opposite direction)
/^string/	Match a line starting with string
/string$/	Match a line ending with string
/\<word\>	Match exact word
/pl[abc]ce	Match patterns like place, plbce, plcce

Replace Text

Command	Action
:1,$ s/old/new/	Replace first occurrence in the entire file
:3,6 s/old/new/g	Replace all matches in lines 3–6
g (modifier)	Makes the substitution global on each line

Text Buffers

Command	Action
"add	Delete line to buffer a
"ap	Paste from buffer a

Set Commands

Command	Description
:set ic	Ignore case when searching
:set ai	Enable auto-indent
:set noai	Disable auto-indent
:set nu	Show line numbers
:set sw=4	Set shift width to 4 spaces
:set ws	Enable wrapscan (search wraps to top)
:set wm=2	Enable word wrap with margin of 2
:set ro	Set file as read-only
:set term	Display terminal type
:set bf	Discard control characters

Summary

The vi editor is a powerful, universal text editor in UNIX/Linux.
It operates in three modes, supports efficient navigation, editing, and text manipulation, and offers customization through set commands. Mastering vi enhances productivity and command-line efficiency.