working with vi Editor - Dr. Balvinder Taneja

Working with the vi Editor

1. Introduction

vi (Visual Editor) is one of the most powerful and commonly used text editors in Linux/UNIX systems. It is a screen-based editor that allows users to create, edit, and manage text files efficiently using the keyboard.

📌 vi is available on almost every Linux system, especially servers.

2. Why vi Editor is Important

Available by default on all Linux systems
Very fast and lightweight
Works in CLI (no GUI required)
Preferred by system administrators
Essential for server configuration files

3. Modes of vi Editor

vi works in three main modes (very important for exams):

1. Command Mode (Normal Mode)

Default mode when vi starts
Used for navigation, deletion, copying, saving
Commands do not appear on screen

📌 Press Esc to return to command mode anytime.

2. Insert Mode

Used to insert or edit text
Text appears on screen

Commands to enter Insert Mode:

i – insert before cursor
a – insert after cursor
o – open new line below
O – open new line above

📌 Press Esc to exit insert mode.

3. Last Line Mode (Ex Mode)

Used for saving, quitting, searching
Commands start with :

📌 Appears at the bottom of the screen.

4. Starting vi Editor

vi filename

Example:

vi file.txt

5. Basic Navigation Commands (Command Mode)

Command	Action
`h`	Move left
`l`	Move right
`j`	Move down
`k`	Move up
`gg`	Go to first line
`G`	Go to last line
`0`	Start of line
`$`	End of line

6. Editing Commands

Insert Mode Commands

Command	Function
`i`	Insert before cursor
`a`	Insert after cursor
`o`	New line below
`O`	New line above

Delete Commands (Command Mode)

Command	Action
`x`	Delete character
`dd`	Delete line
`dw`	Delete word
`d$`	Delete till end

Copy & Paste

Command	Action
`yy`	Copy line
`p`	Paste below
`P`	Paste above

7. Saving and Quitting (Last Line Mode)

Command	Action
`:w`	Save
`:q`	Quit
`:wq`	Save & quit
`:q!`	Quit without saving
`:w filename`	Save as new file

8. Search and Replace

Search

/text

Press n for next occurrence
Press N for previous occurrence

Replace

:%s/old/new/g

Replaces all occurrences

9. Undo and Redo

Command	Action
`u`	Undo
`Ctrl + r`	Redo

10. File Information Commands

:set number     # show line numbers
:set nonumber   # hide line numbers

11. Example: Editing a Configuration File

sudo vi /etc/hosts

Steps:

Press i → insert text
Make changes
Press Esc
Type :wq
Press Enter

12. Advantages of vi Editor

Extremely fast
Keyboard-based efficiency
Minimal system resources
Ideal for servers
Powerful editing features

13. Disadvantages

Steep learning curve
Not beginner-friendly initially

14. Conclusion

The vi editor is a powerful, efficient, and essential tool in Linux. Understanding its modes and commands is crucial for system administration, server management, and exam preparation.