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UNIX - THE VI EDITOR TUTORIAL
http://www
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com/unix/unix-vi-editor
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com

There are many ways to edit files in Unix and for me one of the best ways is using screen-oriented
text editor vi
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Now a days you would find an improved version of vi editor which is called VIM
...

The vi is generally considered the de facto standard in Unix editors because −
It's usually available on all the flavors of Unix system
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It requires very few resources
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You can use vi editor to edit an existing file or to create a new file from scratch
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Starting the vi Editor
There are following way you can start using vi editor −
Command

Description

vi filename

Creates a new file if it already does not exist, otherwise opens existing
file
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view filename

Opens an existing file in read only mode
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A tilde represents an unused line
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So now you have opened one file to start with
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Operation Modes
While working with vi editor you would come across following two modes −
Command mode − This mode enables you to perform administrative tasks such as saving
files, executing commands, moving the cursor, cutting yanking and pasting lines or words, and
finding and replacing
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Insert mode − This mode enables you to insert text into the file
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The vi always starts in command mode
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To come in
insert mode you simply type i
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Hint − If you are not sure which mode you are in, press the Esc key twice, and then you'll be in
command mode
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Getting Out of vi
The command to quit out of vi is :q
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If your file has been modified in any way, the editor will warn you of this, and not let you
quit
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This lets you exit
vi without saving any of the changes
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You can combine the above command with
the quit command, or :wq and return
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When you are in
command mode, type ZZ and it will do the equivalent of :wq
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For example, if
you wanted to save the file you were working as another filename called filename2, you would
type :w filename2 and return
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Moving within a File
To move around within a file without affecting your text, you must be in command mode
pressEsctwice
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j

Moves the cursor down one line
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l

Moves the cursor to the right one character
position
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Most commands in vi can be prefaced by the number of times you want the action to occur
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There are many other ways to move within a file in vi
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Here are some more commands you can use to move around the file −
Command

Description

0 or |

Positions cursor at beginning of line
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w

Positions cursor to the next word
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(

Positions cursor to beginning of current sentence
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E

Move to the end of Blank delimited word

{

Move a paragraph back

}

Move a paragraph forward

[[

Move a section back

]]

Move a section forward

n|

Moves to the column n in the current line

1G

Move to the first line of the file

G

Move to the last line of the file

nG

Move to nth line of the file

:n

Move to nth line of the file

fc

Move forward to c

Fc

Move back to c

H

Move to top of screen

nH

Moves to nth line from the top of the screen

M

Move to middle of screen

L

Move to botton of screen

nL

Moves to nth line from the bottom of the screen

:x

Colon followed by a number would position the cursor on line number
represented by x

Control Commands
There are following useful command which you can use along with Control Key −
Command

Description

CTRL+d

Move forward 1/2 screen

CTRL+d

Move forward 1/2 screen

CTRL+f

Move forward one full screen

CTRL+u

Move backward 1/2 screen

CTRL+b

Move backward one full screen

CTRL+e

Moves screen up one line

CTRL+y

Moves screen down one line

CTRL+u

Moves screen up 1/2 page

CTRL+d

Moves screen down 1/2 page

CTRL+b

Moves screen up one page

CTRL+f

Moves screen down one page

CTRL+I

Redraws screen

Editing Files
To edit the file, you need to be in the insert mode
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I

Inserts text at beginning of current line
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A

Inserts text at end of current line
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O

Creates a new line for text entry above cursor
location
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X

Deletes the character before the cursor location
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d^

Deletes from current cursor position to the beginning of the
line
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D

Deletes from the cursor position to the end of the current line
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As mentioned above, most commands in vi can be prefaced by the number of times you want the

action to occur
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I would highly recommend to exercise all the above commands properly before proceeding
further
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Here
are the relevant commands −
Command

Description

cc

Removes contents of the line, leaving you in insert mode
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r

Replaces the character under the cursor
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R

Overwrites multiple characters beginning with the character currently
under the cursor
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s

Replaces the current character with the character you type
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S

Deletes the line the cursor is on and replaces with new text
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Copy and Past Commands
You can copy lines or words from one place and then you can past them at another place using
following commands −
Command

Description

yy

Copies the current line
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p

Puts the copied text after the cursor
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Advanced Commands
There are some advanced commands that simplify day-to-day editing and allow for more efficient
use of vi −
Command

Description

J

Join the current line with the next one
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<<

Shifts the current line to the left by one shift width
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~

Switch the case of the character under the cursor
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U

Restore the current line to the state it was in before the cursor entered
the line
...
Typing 'u' again will re-do the change
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A count joins that many lines
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:f filename

Renames current file to filename
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:e filename

Opens another file with filename
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:e #

Use to toggle between two opened files
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:p

In case you open multiple files using vi, use :p to go to previous file in
the series
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:r file

Reads file and inserts it after current line

:nr file

Reads file and inserts it after line n
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For a string search, the / and ?
commands are used
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These two commands differ only in the direction where the search takes place −
The / command searches forwards downwards in the file
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The n and N commands repeat the previous search command in the same or opposite direction,
respectively
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Character

Description

^

Search at the beginning of the line
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*

Matches zero or more of the previous character
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[

Starts a set of matching, or non-matching expressions
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>

See the '<' character description above
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The
f and F commands search for a character on the current line only
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The t and T commands search for a character on the current line only, but for t, the cursor moves
to the position before the character, and T searches the line backwards to the position after the
character
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To use
these commands you have to come in command mode then type :set followed by any of the
following options −
Command

Description

:set ic

Ignores case when searching

:set ai

Sets autoindent

:set noai

To unset autoindent
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:set sw

Sets the width of a software tabstop
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:set wm

If this option has a value greater than zero, the editor will automatically
"word wrap"
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To run a command, you only
need to go into command mode and type :! command
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When you press any key orthecommand ′ sescapesequence, you are returned to your vi session
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Here is the simple syntax −
:s/search/replace/g

The g stands for globally
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IMPORTANT
Here are the key points to your success with vi −
You must be in command mode to use commands
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You must be careful to use the proper case capitalization for all commands
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