>> vi editor

vi editor

It is also called visual editor.

To start , in the Unix prompt type vi filename and press enter, the file name could be new or existing.

If new file name is given, new file will be created. If existing file name is given , it opens the existing file which you can edit .

As soon as , you enter vi filename and press ENTER , you will see vi editor window in command mode . You can press "i" to switch to insert mode . In insert mode you can edit the file.

After you  edit the file, you can save it, save and exit or exit without save. To do this, you need to switch to command mode. you can press "Esc" to switch to command mode from insert mode.

In command mode,

":w" press ENTER --- to save the file

":q!" press ENTER --- to quit vi editor without saving the file

":wq" press ENTER --- to save the file and quit vi editor

Vi Editor has two modes of operations :

command mode --- move the cursor, copy/paste,delete, undo, find total lines, line number, search string, sroll page, save. As soon as the vi editor opens, it is in command mode. To switch to insert mode , press "i"

insert mode --- in this mode you can insert  , delete , replace text  to the file.  To switch to command mode , press "Esc".

Vi editor is case sensitive.

insert mode:

As mentioned earlier, as soon as you open vi editor, it is on command mode. To switch to insert mode, type  or press "i"

We will discuss about below characters(insert mode commands), there are more than these which you can practice as per your need . Each character does its unique function.

We will discuss about "i", "I", "o", "O", "a", "A", "s", "S", "C","~", "r"

The functions of each character are mentioned below:

From command mode , press "i " , in the insert mode,  what ever text you enter , will be inserted just  before the cursor position ,ie, the text will be added infront of the cursor moving the cursor to the right.

From command mode , press "I " , the cursor moves to the start of the line and if you enter the text, they will appear in front of the cursor.

From command mode , press "o" , a new line will be added just below the line at which the cursor was there previously. Now, the cursor moves to the  beginning of the new line.

From command mode , press "O" , a new line will be added just above the line at which the cursor was there previously. Now, the cursor moves to the starting of the new line.

From command mode , press "a" ,  the entered text will be added after the original cursor position.

From command mode , press "A" , the cursor moves to the end of the line and the entered text will be added at the end of the line.

From command mode , press "s" , the highlighted character , ie the character at which the cursor is residing , will be deleted.

From command mode , press "S" , the entire line at which the cursor is residing will be replaced as blank. And the cursor will be at the beginning of the line.

From command mode , press "C" , the entire text of the line on the right side of the cursor including the character at which the cursor was residing  will be deleted.

From command mode , press "~" , the case of that character which the cursor is highlighting will be changed ,ie, if lower then will be changed to upper and if upper then will be changed to lower.

From command mode , press "r",  you will see a text " -- REPLACE --" at the bottom of the editor. Press ENTER, the cursor along with the text on right side including the text at which the cursor was previously, moves to the new line.

From command mode , press "r",  you will see a text " -- REPLACE --" at the bottom of the editor. Press any character , that character will replace the existing text .

This way you can practice with other  insert mode commands  ,upper case and lower case, as per your need.

Command mode

We will discuss about below commands(in command mode):

h , l , j , k , L , H , M , G , 3G , w , :n , :$ , 0 , x , dd , yy , p , u , ^ , $ ,  /search   ,  n  ,  ?search , N , := , :.=  , :f , keyboard keys(CTRL + U/D/F/B/H/M)

h --- moves the cursor to the  left , one character each time you press "h" 

l --- moves the cursor to the right, one character each time you press "l"

j --- moves the cursor one line down each time you press "j"

k ---moves the cursor one line up each time you press "k"

Note : you can use your keyboard arrows also to move the cursor to the left, right, up, down

L --- moves the cursor to the beginning of the last line on the screen

H --- moves the cursor to the beginning of the first line on the screen

M ---  moves the cursor to the beginning of the middle line on the screen

G --- moves the cursor to the beginning of the last line of the file

3G --- moves the cursor to the beginning of the 3rd line of the file, you can give any number with the letter "G" and the cursor moves to the respective line of the file.

w --- moves the cursor to the beginning of the next word on the right side.

:n  --- :3 will move the cursor to the beginning of 3rd line, :6 will move the cursor to the beginning of 6th line and so on.

:$ --- goes to beginning of last line.

0 --- moves the cursor to the beginning of the line(this is zero not the character "o").

x --- deletes the character which the cursor is at ,ie, which the cursor is highlighting.

dd --- deletes the entire line at which the cursor was there and the below line moves one step up and the cursor is at the beginning of that line.

yy --- copies the line at which the cursor is .

p --- paste the copied line just below the line at which the cursor is .

P --- paste the copied line just above the line at which the cursor is .

u ---  this will undo the activities done previously. Press "u" more , more previous activities will be undone.

^ --- cursor moves to the front of the line

$ --- cursor moves to the end of the line.

/text  press ENTER  --- searches the text in clockwise direction , ie, from left to right and if the cursor does not find on the right side then the first word from the top.

n ---  when you search the text using "/text" and pressing ENTER, once ENTER is pressed now to search another occurrence of the same text just press "n" ,ie, repeat the last search forward.

?text and press ENTER --- when you type ?text and press ENTER , you search the text in backward direction , ie, right to left and in the anti-clockwise direction . And pressing "n" in this situation , searches the next occurrence of the same text in backward direction, ie, repeat the last search backward.

N --- as discussed above, pressing "n" will repeat the previous search forward or backward. After searching the text , pressing "N" will do the search in opposite direction of "n".

:=  --- displays the total number of the line

:.=  --- displays current line number

:f --- shows file name and the current line of the cursor and total lines.

Keyboard keys

CTRL+u(or U) --- To scroll the screen half up

CTRL+d(or D) --- To scroll the screen half down

CTRL+f(or F) --- To move forward by one screen

CTRL+b(or B) --- To move backward by one screen

CTRL+h(or H) --- moves the cursor one step back ,if at the beginning of the line , then it moves to the end of upper line.

CTRL+m(or M) --- moves the cursor one step forward ,if at the end of the line , then it moves to the beginning of the below line.