About VI Editor

By Raj Last updated Jan 16, 2016

Editor, vi tutorial vi Editor, Learn vi, About vi editor

vi is Found on Nearly Every Unix Computer
vi is the standard Unix editor
vi is Powerful and Fast
Your terminal displays a section of the file you are editing
vi can do anything you want
You don’t need to remove your fingers from the standard typing keys-the keys themselves give commands to vi
vi Stays Out of Your Way
vi has no menus
vi commands are short Starting vi Open a file with vi.
Type: vi myfile.txt If myfile.txt does not exist, a screen will appear with just a cursor at the top followed by tildes(~) in the first column.If myfile.txt does exist, the first few line of the file will appear.The status line at the bottom of your screen shows error messages and provides information and feedback, including the nameof the file.

Modes:

Command Mode:

Command mode is the mode you are in when you start (default mode)
Command mode is the mode in which commands are given to move around in the file, to make changes, and to leave the file
Commands are case sensitive: j not the same as J
Most commands do not appear on the screen as you type them. Some commands will appear on the last line: : / ?

Insert (or Text) Mode:

The mode in which text is created. (You must press at the end of each line unless you’ve set wrap margin.)
There is more than one way to get into insert mode but only one way to leave: return to command mode by pressing
When in doubt about which mode you are in, press Basic Cursor Movement
k Up one line
j Down one line
h Left one character
l Right one character (or use )
w Right one word
b Left one word

NOTE: Many vi commands can take a leading count (e. g., 6k, 7e).

Entering, Deleting, and Changing Text

i	Enter text entry mode
x	Delete a character
dd	Delete a line
r	Replace a character
R	Overwrite text, press to end

Setting Basic Options in vi:

Displaying Line Numbers

:set nu	Display line numbers
:set nonu	Hide line numbers

Setting Right Margin

:set wm=number	Set Wrap Margin number of spaces from right edge of screen
:set wm=10	Set Wrap Margin 10 spaces from right edge of screen
:set wm=0	Turn off Wrap Margin

Exiting vi

To exit you must be in command mode-press if you are not in command mode

You must press after commands that begin with a : (colon)

ZZ	Write (if there were changes), then quit
:wq	Write, then quit
:q	Quit (will only work if file has not been changed)
:q!	Quit without saving changes to file

Basics Summary:

A Basic vi Session

To enter vi, type: vi filename

To enter insert mode, type: i

Type in the text: This is easy.

To leave insert mode and return to command mode, press:

In command mode, save changes and exit vi by typing: :wq

You are back at the Unix prompt.

Intermediate VI:

More On Cursor Movement

e	Move to end of current word
$	Move to end of current line
^	Move to beginning of current line
+	Move to beginning of next line
–	Move to beginning of previous line
G	Go to last line of the file
:n	Go to line with this number (:10 goes to line 10)
d	Scroll down one-half screen
u	Scroll up one-half screen
f	Scroll forward one full screen
b	Scroll backward one full screen
)	Move to the next sentence
(	Move to the previous sentence
}	Move to the next paragraph
{	Move to the previous paragraph
H	Move to the top line of the screen
M	Move to the middle line of the screen
L	Move to the last line of the screen
%	Move to matching bracket: ( { [ ] } )

Entering Text Mode

i	Insert text before current character
a	Append text after current character
I	Begin text insertion at the beginning of a line
A	Append text at end of a line
o	Open a new line below current line
O	Open a new line above current line

Commands and Objects

Format	Example
operator number object	c2w
number operator object	2cw

Operators

c	change
d	delete
y	yank

Objects and Locations

w	one word forward
b	one word backward
e	end of word
H, M, L	top, middle, or bottom line on screen
), (	next sentence, previous sentence
}, {	next paragraph, previous paragraph
^, $	beginning of line, end of line
/pattern/	forward to pattern

Replacing and Changing Text

r	Replace only the character under the cursor. (Note: using r you remain in command mode.)
R	Beginning with the character under the cursor, replace as many characters on this line as you want. (You are in overtype mode until you press
cw	Beginning with the character under the cursor, change a word to whatever you type. (You are in insert mode until you press )
c$	Beginning with the character under the cursor,
C	change a line to whatever you type. (You are in insert mode until you press )

Deleting Text

	Delete a character
dw	Delete an alphabetic word and the following space (6dw deletes six words)
dW	Delete a blank-delimited word and the following space
dd	Delete a line (6dd deletes six lines)
d$	Delete all characters to the end of the line.
d}	Delete all characters to the end of the paragraph.
:5,30d	Delete lines 5 through 30

Deleted text goes into a temporary buffer that is replaced each time you delete (or copy) more text. The current contents of

the buffer can be put back into your file.

Copying and Pasting Text

yy	Copy (yank) the current line
6yy	Copy (yank) six lines, beginning with the current line
yw	Copy the current word
p	Put the text after the cursor position
P	Put the text before the cursor position

Copied text goes into a temporary buffer that is replaced each time you copy (or delete) more text. Only the current contents of the temporary buffer can be put back into your file. As a result, when you use copy (y), use the put (p) command immediately.A yank and put procedure using colon commands:

:5,10y Copy lines 5-10

Move cursor

:put Put after cursor

Other Useful Commands

.	Repeat last command
n.	Repeat last command n number of times
J	Join next line to current line
u	Undo last single change
U	Restore current line
~	Change letter’s case (capital to lower and vice versa)

Temporary Buffer

Deleted or copied text goes into a temporary unnamed buffer. The contents of the temporary buffer may be retrieved by using the p or P commands.

p	Put words from temporary buffer after cursor or put lines from temporary buffer below current line
P	Put words from temporary buffer before cursor or put lines from temporary buffer above current line

Lettered Buffers

There are 26 lettered buffers (a-z). Contents of a lettered buffer are saved until you copy or delete more characters into it, or until you quit your current vi session.

“ayy	Copy (yank) a line into buffer a
“Ayy	Appends to buffer a
“a10yy	Copies 10 lines into buffer a
“a10dd	Deletes 10 lines of text into buffer a
“ap	Put contents of lettered buffer a below the current line

Both temporary and lettered buffers last only for the current vi session. Copying, Deleting, or Moving Text Using Line Numbers These commands start with a colon (:) and end with a or g shows the line number of the current line The basic form of colon commands is

:beginning_line, ending_line command destination

where destination is the line after which you want the text placed.

:5,10 co 105	Copy lines 5-10 to the line after 105
:5,20 m $	Move lines 5-20 to end of file
:7,300 d	Delete lines 7-300 (to buffer)

Searching for Text

/text	Search forward (down) for text (text can include spaces and characters with special meanings.)
?text	Search backward (up) for text
n	Repeat last search in the same direction
N	Repeat last search in the opposite direction
fchar	Search forward for a charcter on current line
Fchar	Search backward for a character on current line
;	Repeat last character search in the same direction
%	Find matching ( ), { }, or [ ]

Substitutions

The simplest way to do substitutions over a range of lines, or throughout the file, is to use the s colon command. The basic form of this command is the following:

:n1,n2s/old/new/gc

n1	is the beginning line
n2	is the ending line number
s	means to substitute text matching the pattern (old) with text specified by(new)
g (global)	is optional. It indicates you want to substitute all occurrences on the indicated lines. If you use g, the editor substitutes only the first occurrence on the indicated lines.
c (confirm)	is optional. It indicates you want to confirm each substitution before vi completes it.

:%s/old/new/g	Substitutes old with new throughout the file
:.,$s/old/new/g	Substitutes old with new from the current cursor position to the end of the file
:^,.s/old/new/g	Substitutes old with new from the beginning of the file to the current cursor position
:&	Repeats the last substitute (:s) command

Advanced VI Tutorial:

Writing to and Reading from Files

:w file	Write current file to file
:w>>file	Append current file to file
:5,10w file	Write lines 5 through 10 to file
:5,10w>>file	Append Lines 5 through 10 to file
:r file	Read a copy of file into current file
:!ls	See a list of files in your current directory

More About Options:
From Command Mode-within vi for the current file only

:set all	Display all options
:set	Display current settings of options
:set nooption	Unset option
:set ai	Set Auto Indentation during text entry
:set ic	Set Ignore Case during searches
:set nu	Show line Numbers
:set sm	Show Matching ( or { when ) or } is entered
:set wm=10	Set Wrap Margin 10 spaces from right edge of screen

Customizing vi Sessions:
Options can be set four ways:

During a vi session
- :set nu
In a .exrc file in your home directory.
Sample contents of a .exrc file
set nu
set ai
set wm=10
In a .exrc file in a subdirectory.
By setting the EXINIT environmental variable.
Example of setting the EXINIT environmental variable
setenv EXINIT “set nu ai ic”Order of Precedence
If a .exrc file exists in the current directory, vi reads it when beginning a session.
If no .exrc file exists in the current directory, vi checks the home directory for a .exrc file. If such a file exists,vi reads it when beginning a session.
If no .exrc file is found, vi uses its defaults.
Values set in the EXINIT environmental variable override any values set in a .exrc file. Creating a .exrc File At the system prompt, type: vi .exrcType the following commands, each on a separate line:
set ai
set ic
set nu
set wm=8Do not leave blank lines at the beginning or end of the .exrc file.When you are finished, type: Abbreviations & Mapping. Abbreviations are text strings that automatically expand into larger strings during insert mode.:ab UW University of WashingtonMapping defines a single key to execute a sequence of keystrokes when the single key is pressed in command mode. In thefollowing example,the @ key is mapped to replace the current word with “University of Washington”. The v allows youto enter the key into the command sequence.:map @ cwUniversity of Washington vMapping can also be used to call commands external to vi, such as sort or fmt. In the following example, the @ sign is mapped to the sort command, so that the current paragraph (indicated by the }) will be sorted. The v allows you to enter the key into the command sequence. The second completes the map command.:map @ !}sort vNote: You can also put abbreviation and mapping commands in your .exrc file.

Tips And Tricks:

Find the line that readseditor=Change it to readeditor=viWrite and quit the file. (ZZ or :wq)vi-ing More Than One FileYou can edit more than one file at a time with vi.

From The Unix Shell Prompt

vi file1 file2 vi two (or more) files at the same time

From Command Mode

:n	Move to file2 from file1
:rew	Rewind back to file1
:e!	Restore original file1 file2 (start all over)
ZZ	Save and quit file. (Must be done for each file.)

Moving the Left Margin

When you print a file you may want the left margin moved to the right. This leaves room for a three-hole punch.

:1,$>	Move entire file 1 shift width (eight spaces) to the right
:1,$<	Move entire file eight spaces to the left
:%s/^/ /g	Insert any number of spaces at the beginning of each line in the entire file. Simply press the space bar the desired number of times.
:20>>	Moves next 20 lines over 1 shift width.

Issuing Shell Commands From vi

You can issue a single shell command while in the vi editor. For example, to list the files in your directory (ls), follow these steps:

Press d to return to vi editing.

Double Spacing a File

Occasionally, you may want a double spaced version of your file for editing or review.

:w	Write changes to your file (just in case).
:!ls	List contents of your current directory on the screen.Press to return to vi.You can issue many shell commands by temporarily leaving the vi editor.From Command Mode
:w	Write changes to your file.
:sh	Return to the shell to enter a number of commands without leaving vi.

:w	original.backup Save a backup copy of the original file
:%! sed G	Double space the entire file.
:1,5! sed G	Double space the lines from 1-5.

Original Author: M.S.Verman

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