Understanding VI editor

VI editor is a screen-oriented text editor written by Bill Joy in 1976. This is the most commonly used editor for editing files in Linux.

VI Editor Modes

Three modes are commonly using in VI editor. They are:

Insert Mode
Command Mode
Ex-Mode (Extended Command Mode)

Insert Mode

In Insert Mode, we can perform the operations like adding, deleting and editing the existing text of a file.

 i    Inserts the text at the current cursor position 
 I    Inserts the text in beginning of the line  
 a    Adds the text after the current cursor position 
 A    Adds the text at the end of a line 
 o    Inserts the text one line below current cursor position 
 O    Inserts the text one line above current cursor position

Command Mode

This is the default mode of VI editor in which we can perform the operations like Copy, Paste and Delete the lines.

 dd       Deletes a line
 ndd      Deletes 'n' lines
 dw       Deleted a word next to the cursor
 yy       Copies a line
 nyy      Copies 'n' lines
 yw       Copies a word next to the cursor
 p        Pastes the deleted or copied text
 u        Undo (you can undo 1000 times)
 Ctrl+r   Redo
 G        Move cursor to the last line of the file
 /<word>  Finds a word (Press 'n' for next)

Ex-Mode (Extended Command Mode)

The Ex mode is similar to the command mode as it also allows you to enter Ex commands. It is optimized for batch processing.

 
 :q        Quit without saving
 :q!       Quit forcefully without saving
 :w        Write (Save)
 :wq       Save and quit
 :wq!      Save and quit forcefully
 :se nu    Sets the line numbers
 :se nonu  Removes line numbers
 :24       Cursor goes to line 24
 :wn       Save and switch to next file
 :rew      Change last file (rewind)