vi & vim
1. Background introduction and the difference between vi and vim
vi is the default editor of linux system, maybe you will ask? What is the difference between vi and vim? In fact, vim is an upgraded version of vi. In my opinion, the biggest difference between vi and vim is that when editing a total of text, vi will not display colors, but vim will display colors.
2. If your system does not have vim, execute the following statement
yum install -y vim-enhanced
3. Brief introduction to vim
There are three modes of vim: general mode, editing mode, and command mode, which we need to keep in mind.
3.1 General mode
When we use the command vim filename to edit a file, it enters the general mode of the file by default. In this mode, you can do operations: move the cursor up and down, delete a character, delete a line, and copy and paste one or more lines.
| button | Use |
|---|---|
| h or the left arrow key | Move the cursor one character to the left |
| l (lowercase letter) or right arrow key | Move the cursor one character to the right |
| k or up arrow key | Cursor up one character |
| j or the left arrow key | Cursor down one character |
| Ctrl + B | Turn the text page forward one page |
| Ctrl + F | Turn the text page back one page |
| Number 0 or shift + 6 | Move to the beginning of this line |
| shift + 4 | Move to the end of the line |
| gg | Move to the first line |
| G | Move to the end |
| nG (n is any number) | Move to line n |
In the general mode, we can also implement operations such as copying, deleting, and pasting characters or strings, as shown in the following table
| button | effect |
|---|---|
| x or x | x means delete one character backward, X means delete one character forward |
| nx | Delete n characters backward |
| dd | Delete/cut the line where the cursor is |
| ndd (n is the abbreviation of number) | Delete/cut n lines after the line where the cursor is |
| yy | Copy the line where the cursor is |
| nyy | From the line where the cursor is located, copy n lines down |
| p | Starting from the line where the cursor is located, paste down the copied or pasted content |
| P | Starting from the line where the cursor is, paste the copied or pasted content upwards |
| u | Restore the previous operation |
| v | After pressing v, moving the cursor will select the specified character, and then copy, paste and other operations can be realized |
3.2 Edit mode
You cannot modify a character in the general mode. If you want to modify a character, you can only enter the edit mode. To enter edit mode from normal mode , just press one of i, I, a, A, o, O, r, or R. When entering the edit mode, the word INSERT or REPLACE will be displayed at the end of the screen (if your centos supports Chinese, it will display "Insert"). **To return to normal mode from edit mode, just press Esc key. **As shown below
| button | Use |
|---|---|
| i | Insert before the current character |
| I | Insert at the beginning of the line where the cursor is |
| a | Insert after the current character |
| A | Insert at the end of the line where the cursor is |
| The | Insert a new line below the current line |
| THE | Insert a line above the current line |
3.3 Command mode
In the normal mode, enter: or / to enter the command mode. In this mode, we can search for a character or string, and can also perform operations such as saving, replacing, exiting, and displaying line numbers, as shown in the following table
| button | Use |
|---|---|
| /word | Find a string word after the cursor, press n to continue searching backward |
| ?word | Find a string word before the cursor, press n to continue searching forward |
| :n1,n2s/word1/word2/g | Find word1 between lines n1 and n2 and replace it with word2, without g, only replace the first word1 of each line |
| :1,$s/word1/word2/g | Replace all word1 in the document with word2, and replace only the first word1 in each line without g |
Other functions are as follows
| button | Use |
|---|---|
| :w | Save text |
| :q | Exit vim |
| :w! | Forced to save, under the root user, even if the text is read-only, it can be saved |
| :q! | Force exit, all changes will not take effect |
| :wq | Save and exit |
| : set no | Show line number |
| :set nonu | Do not display line numbers |