VI Text Editor

The VI Editor is the standard editor for all UNIX and Linux systems, the VI editor is exactly the same for any version of UNIX and Linux systems, its power is not inferior to any of the latest text editors, VI is also the most basic text editor in Linux, after learning it, You will be in the world of Linux.
1, VI of the basic concept

Basically, vi can be divided into three states, namely command mode, insert mode (and bottom line mode), and the function of each mode is as follows:

1) command-line mode
Controls the movement of the screen cursor, the deletion of characters, words, or lines, moving and copying a section and entering insert mode, or to last line mode.

2) Insert mode
Only in the Insert mode, you can do text input, press "esc" to return to the command line mode.

3) Bottom Line mode
Save or Exit VI, or you can set the editing environment, such as looking for a string, listing line numbers ... such as

In general, however, we simplify the VI to two modes in use, namely: command line and insert mode (the bottom line mode is also counted as command-line mode)).

2, VI of the basic operation
A) Enter VI

After the system prompt symbol to enter VI and file name, go to the VI Full screen editing screen:
$ VI myfile
However, it is important to note that after you enter VI, you are in command mode and you want to switch to insert mode to enter text.

b) switch to insert mode to edit the file
Press the letter "i" under Command mode to enter "Insert Mode", and you can start typing the text again at this point.

c) Toggle of Insert
You are currently in "Insert Mode", you can only enter text, if you find the wrong word! To move back with the cursor key, delete the word, then click the "esc" key to go to "command mode" and then delete the text.

d) Exit VI and save the file
Under Command mode, click the ":" colon key to enter "last line mode", for example:

: w filename (enter "w filename" to save the article with the filename you specified)
: Wq (input "wq", save and Exit VI)
: q! (Enter q!, do not save the mandatory exit VI)

3. Command mode function key

1). Insert mode
Press "i" switch into insert mode "insert mode", press "I" into the insertion mode is the beginning of the cursor from the current position to enter the file;
After pressing "a" into insert mode, the text is entered from the next position at the current cursor position;
When you press "o" to enter insert mode, you insert a new line and enter text from the beginning of the beginning.

2). Switch from insert mode to command line mode
Press the "esc" key.

3). Move the cursor
VI can be directly on the keyboard with the cursor to move up and down, but the normal VI is the lowercase English letter "h", "j", "k", "l", respectively, control the cursor left, bottom, upper, and right one grid.
Press "ctrl"+"b": The screen moves one page to the back.
Press "ctrl"+"f": The screen moves one page to the front.
Press "ctrl"+"u": The screen moves the half page toward the back.
Press "ctrl"+"d": The screen moves the half page toward the front.
"0" by number: Moves to the beginning of the article.
Press "g": Move to the end of the article.
Press "$": Moves to the end of the line where the cursor is located.
Press "^": Moves to the beginning of the line where the cursor is located
Press "w": Cursor jumps to the beginning of the next word
Press "e": Cursor jumps to the end of the next word
Press "b": Cursor back to the beginning of the last word
Press #l: The cursor moves to the first # position of the line, such as: 5l,56l.

4). Delete text

"x": Each time you press the cursor, delete the "after" character at the position where the pointer is located.
#x: For example, "6x" represents the "after" 6 characters of the location where the cursor was deleted.
"x": Uppercase X, each time it is pressed, deletes the "front" character at the location of the cursor.
"#X": for example, "20x" represents the "front" 20 characters of the location where the cursor was deleted.
"dd": Delete the line where the cursor is located.
"#dd": Deletes the # line starting at the line where the cursor is located

5). Copy

"yw": Copies the characters from the cursor to the end of the word into the buffer.
"#yw": Copy # words to Buffer
"yy": Copy cursor line to buffer.
"#yy": for example, "6yy" represents a copy of 6 lines of text from the line where the cursor is located.
"p": Paste the characters in the buffer to the cursor location. Note: All copy commands related to "Y" must be mated with "P" to complete the copy and paste function.

6). Replace

"r": Replaces the character at which the cursor is located.
"r": Replaces the character where the cursor is located until the "esc" key is pressed.

7). Reply to Last action
"u": If you mistakenly execute a command, you can press "u" immediately to go back to the previous action. Multiple replies can be performed by pressing "U" multiple times.

8). Change

"cw": Change the word-to-tail at the cursor location
"c#w": For example, "c3w" represents a change of 3 words

9). Jump to the specified line

"ctrl"+"g" lists the line number of the line where the cursor is located.
"#G": for example, "15g", which means moving the cursor to the beginning of the 15th line of the article.

4. Next line Mode command brief

Before using "last line mode", remember to press "esc" to make sure you are under "command mode" and then press ":" Colon to enter "last line mode".

A) List line numbers
"set nu": After you enter "set nu", the line numbers are listed before each line in the file.

B) jump to a line in the file
The "#":"#" number represents a number, enter a number after the colon, and then press ENTER to jump to the line, such as entering the number 15, and then enter, you will jump to the 15th line of the article.

C) Find characters
"/Keyword: First press the"/"key, and then enter the character you want to look for, if the first keyword is not what you want, you can always press"n"will look back to the keyword you want.
"? keyword": Press "?" first Key, and then enter the character you want to find, if the first keyword is not what you want, you can always press "n" will look forward to the keyword you want.

D) Save the file
"w": Enter the letter "w" the colon to save the file.

E) Leave VI
"q": Press "q" is to exit, if you cannot leave VI, can be "q" followed by a "!" Forced to leave VI.
"qw": Generally recommended to leave, use with "w", so you can also save the file when exiting.

2, the following table lists some instructions in the line command mode
W filename
Save the file you are editing as filename

WQ filename
Save the file being edited as filename and exit VI

Q!
Discard all changes, exit VI

Set Nu
Show line Numbers

Or?
Find, enter what you are looking for in/after

N
with/or, if the search is not the keyword you are looking for, press N or backwards (with/to) or forward (with?) to continue looking until you find it.

For the first use VI, there are a few notes to remind:

1. When you open a file with VI, you are in command mode, and you want to switch to insert mode to enter text. Toggle method: Click on the letter "i" "Command mode" to enter "Insert Mode", then you can start to enter the text.
2, after editing, you need to switch from insert mode to command line mode in order to save the file, switch method: Press the "esc" key.
3. Save and exit the file: Enter in command mode: WQ! (Don't forget to wq the front:)

Reference: https://www.cnblogs.com/ovliverlin/articles/1162430.html

VI Text Editor