linux vi

1.Three command modes of VI:
  1) Command (command) mode, which is used to enter commands;
  2) Insert (insert) mode, which is used to insert text;
  3) Visual (visual) mode, which is used for visual high-level

2. Save and exit the file
  2.1):w save;
  2.2):w filename save as filename;
  2.3):wq! save and exit; 2.4
  ):wq! filename Note: save with filename as the file name
  2.5):q! Exit without saving; 2.6
  ):x should save and exit, the function is the same as :wq!

3. Cursor move
  3.1)j move down one line;
  3.2)k move up one line;

  3.3)h
  3.4)l move one character to the right; 3.5

  )ctrl+b move up one screen;
  3.6)ctrl+f move down one screen;

  3.7)up arrow move up;
  3.8)down arrow down move;
  3.9) left arrow move left;
  3.10) right arrow move right;

  3.11) $ move to end of line
  3.12) gg move to beginning of document
  3.13) GG move to end of document
  3.14) ctrl + f page forward
  3.15) ctrl + b page backward

4. Insert mode
  4.1) i insert before the cursor;
  4.2) a insert after the cursor;

  4.3) i insert at the beginning of the line where the cursor is located;
  4.4)A insert at the end of the line where the cursor is located;

  4.5)O insert a line above the line where the cursor is located;
  4.6)o insert a line below the line where the cursor is located;

  4.7)s delete a character after the cursor, and then enter the insert mode;
  4.8)S delete the line where the cursor is, and then enter the insert mode;

5. Delete text content
  5.1)x a character;
  5.2)#x delete several characters, # means a number, such as 3x;
  5.3)dw delete a word ;
  5.4)#dw delete several words, # is represented by numbers, such as 3dw means delete three words;
  5.5)dd delete one line;
  5.6)#dd delete multiple lines, # represents numbers, such as 3dd means delete cursor line and cursor
  5.7)d$ Delete the content from the cursor to the end of the line; 5.8
  )J Clear the space between the line where the cursor is located and the previous line, and connect the cursor line and the previous line together;

6.Restore modification and recovery Delete
  6.1) u undo the modification or deletion operation;

7. Visual mode
  The visual mode is provided by vim, vi has no visual mode, if we want to call vim when we type vi ***.txt, we can enter the following command:
  echo alias vi=vim >> /etc/profile
  After the next login, Use the vi command to open the file to directly call vim

8. Copy and paste
  8.1)yy copy the current line
  8.2)#yy copy multiple lines, # is represented by numbers, such as 3yy to copy three lines;
  8.3) If in visual mode , y can copy the selected content

  8.4) p paste after the cursor
  8.5) shift + p paste before the cursor

9. Find and replace
  9.1)/SEARCH Note: forward search, press the n key to move the cursor to the next
  9.2)?SEARCH Note: reverse search, press shift+n, move the cursor to the next qualified place 9.3

  ):s /SEARCH/REPLACE/g Note: put the current cursor in the line
  9.4):%s /SEARCH/REPLACE Note: Replace all SEARCH in the document with REPLACE; 9.5
  ):#,# s /SEARCH/REPLACE/g Note : The # sign represents a number, from how many lines to how many lines, replace SEARCH with REPLACE