What is
vi?
The default editor that comes with the UNIX operating system is called
vi (
visual editor). [Alternate editors for UNIX environments include
pico and
emacs, a product of GNU.]
The UNIX
vi editor is a full screen editor and has two modes of operation:
- Command mode commands which cause action to be taken on the file, and
- Insert mode in which entered text is inserted into the file.
In the command mode, every character typed is a command that does something to the text file being edited; a
character typed
in the command mode may even cause the
vi editor to enter the insert mode. In the insert mode, every character typed is added to the text
in
the file; pressing the
<Esc> (
Escape) key turns off the Insert mode.
While there are a number of
vi commands, just a handful of these is usually sufficient for beginning
vi users. To assist such users, this Web page contains a sampling of basic
vi commands. The most basic and useful commands are marked with an asterisk (
* or star) in the tables below. With practice, these commands should become automatic.
NOTE: Both UNIX and
vi are
case-sensitive. Be sure not to use a capital letter in place of a lowercase letter; the results will not be
what
you expect.
To Get Into and Out Of
vi
To Start
vi
To use
vi on a file, type in
vi filename. If the file named
filename exists, then the first page (or screen) of the file will be displayed; if the file does
not
exist, then an empty file and screen are created into which you may enter text.
| * |
vi filename
|
edit
filename starting at line 1
|
vi -r filename
|
recover
filename that was being edited when system crashed
|
To Exit
vi
Usually the new or modified file is saved when you leave
vi. However, it is also possible to quit
vi without saving the file.
Note: The cursor moves to bottom of screen whenever a colon (
:) is typed. This type of command is completed by hitting the
<Return> (or
<Enter>) key.
| Basic Command | Command | Description |
|---|---|---|
| here |
:x
<Return>
|
quit
vi, writing out modified file to file named in original invocation
|
:wq
<Return>
|
quit
vi, writing out modified file to file named in original invocation
|
|
:q
<Return>
|
quit (or exit)
vi
|
|
| * |
:q!
<Return>
|
quit
vi even though latest changes have not been saved for this
vi call
|
Moving the Cursor
Unlike many of the PC and MacIntosh editors,
the mouse does not move the cursor within the
vi editor screen (or window). You must use the the key commands listed below. On some UNIX
platforms,
the arrow keys may be used as well; however, since
vi was designed with the Qwerty keyboard (containing no arrow keys) in mind, the arrow keys
sometimes
produce strange effects in
vi and should be avoided.
If you go back and forth between a PC environment and a UNIX environment, you may find that this dissimilarity in methods for cursor movement is the most frustrating difference between the two.
In the table below, the symbol
^ before a letter means that the
<Ctrl> key should be held down while the letter key is pressed.
| Basic Command | Command | Description |
|---|---|---|
| * |
j
or
<Return> [
or down-arrow]
|
move cursor down one line |
| * |
k [
or up-arrow]
|
move cursor up one line |
| * |
h
or
<Backspace> [
or left-arrow]
|
move cursor left one character |
| * |
l
or
<Space> [
or right-arrow]
|
move cursor right one character |
| * |
0 (zero)
|
move cursor to start of current line (the one with the cursor) |
| * |
$
|
move cursor to end of current line |
w
|
move cursor to beginning of next word | |
b
|
move cursor back to beginning of preceding word | |
:0
<Return>
or 1G
|
move cursor to first line in file | |
:n
<Return>
or nG
|
move cursor to line
n
|
|
:$
<Return>
or G
|
move cursor to last line in file |
Screen Manipulation
The following commands allow the
vi editor screen (or window) to move up or down several lines and to be refreshed.
| Basic Command | Command | Description |
|---|---|---|
^f
|
move forward one screen | |
^b
|
move backward one screen | |
^d
|
move down (forward) one half screen | |
^u
|
move up (back) one half screen | |
^l
|
redraws the screen | |
^r
|
redraws the screen, removing deleted lines |
Adding, Changing, and Deleting Text
Unlike PC editors, you cannot replace or delete text by highlighting it with the mouse. Instead use the commands in the following tables.
Perhaps the most important command is the one that allows you to back up and undo your last action. Unfortunately, this command acts like a toggle, undoing and redoing your most recent action. You cannot go back more than one step.
| * |
u
|
UNDO WHATEVER YOU JUST DID; a simple toggle |
The main purpose of an editor is to create, add, or modify text for a file.
Inserting or Adding Text
The following commands allow you to insert and add text. Each of these commands puts the
vi editor into insert mode; thus, the
<Esc> key must be pressed to terminate the entry of text and to put the
vi editor back into command mode.
| Basic Command | Command | Description |
|---|---|---|
| * |
i
|
insert text before cursor, until
<Esc> hit
|
I
|
insert text at beginning of current line, until
<Esc> hit
|
|
| * |
a
|
append text after cursor, until
<Esc> hit
|
A
|
append text to end of current line, until
<Esc> hit
|
|
| * |
o
|
open and put text in a new line below current line, until
<Esc> hit
|
| * |
O
|
open and put text in a new line above current line, until
<Esc> hit
|
Changing Text
The following commands allow you to modify text.
| Basic Command | Command | Description |
|---|---|---|
| * |
r
|
replace single character under cursor (no
<Esc> needed)
|
R
|
replace characters, starting with current cursor position, until
<Esc> hit
|
|
cw
|
change the current word with new text, starting with the character under cursor, until
<Esc> hit
|
|
cNw
|
change
N words beginning with character under cursor, until
<Esc> hit; e.g.,
c5w changes 5 words
|
|
C
|
change (replace) the characters in the current line, until
<Esc> hit
|
|
cc
|
change (replace) the entire current line, stopping when
<Esc> is hit
|
|
Ncc
or
cNc
|
change (replace) the next N lines, starting with the current line, stopping when
<Esc> is hit
|
Deleting Text
The following commands allow you to delete text.
| Basic Command | Command | Description |
|---|---|---|
| * |
x
|
delete single character under cursor |
Nx
|
delete N characters, starting with character under cursor | |
dw
|
delete the single word beginning with character under cursor | |
dNw
|
delete
N words beginning with character under cursor; e.g.,
d5w deletes 5 words
|
|
D
|
delete the remainder of the line, starting with current cursor position | |
| * |
dd
|
delete entire current line |
Ndd
or
dNd
|
delete
N lines, beginning with the current line; e.g.,
5dd deletes 5 lines
|
Cutting and Pasting Text
The following commands allow you to copy and paste text.
| Basic Command | Command | Description |
|---|---|---|
yy
|
copy (yank, cut) the current line into the buffer | |
Nyy
or
yNy
|
copy (yank, cut) the next N lines, including the current line, into the buffer | |
p
|
put (paste) the line(s) in the buffer into the text after the current line |
Other Commands
Searching Text
A common occurrence in text editing is to replace one word or phase by another. To locate instances of particular sets of characters (or strings), use the following commands.
| Basic Command | Command | Description |
|---|---|---|
/string
|
search forward for occurrence of
string in text
|
|
?string
|
search backward for occurrence of
string in text
|
|
n
|
move to next occurrence of search string | |
N
|
move to next occurrence of search string in opposite direction |
Determining Line Numbers
Being able to determine the line number of the current line or the total number of lines in the file being edited is sometimes useful.
| Basic Command | Command | Description |
|---|---|---|
:.=
|
returns line number of current line at bottom of screen | |
:=
|
returns the total number of lines at bottom of screen | |
^g
|
provides the current line number, along with the total number of lines, In the file at the bottom of the screen |
Saving and Reading Files
These commands permit you to input and output files other than the named file with which you are currently working.
| Basic Command | Command | Description |
|---|---|---|
:r filename
<Return>
|
read file named
filename and insert after current line (the line with cursor)
|
|
:w
<Return>
|
write current contents to file named in original
vi call
|
|
:w newfile
<Return>
|
write current contents to a new file named
newfile
|
|
:12,35w smallfile
<Return>
|
write the contents of the lines numbered 12 through 35 to a new file named
smallfile
|
|
:w! prevfile
<Return>
|
write current contents over a pre-existing file named
prevfile
|