Summary and sharing of vi in ​​Linux commands (collection)

This article mainly introduces the detailed arrangement (summary) of Linux file editing commands. The editor thinks it is quite good, so I will share it with you now and give it as a reference. Let’s follow the editor and take a look.

I’m new to Linux. I applied for a free trial Alibaba Cloud server a few days ago. I chose the Ubuntu system. When configuring the jdk environment variables, I need to edit the file.

vi command to edit files, I searched on Baidu, and many of the answers were not very comprehensive, so it took some time to edit the file.

The blogger here has sorted it out and shared it with everyone.

1. The vi editor has 3 basic working modes

First of all, you need to know that the vi editor has 3 basic working modes, namely : Command mode, text input mode, and last line mode.

First: Command line mode: This mode is the default mode after entering the vi editor. At any time, no matter what mode the user is in, pressing the ESC key can enter command mode. In this mode, users can enter vi commands and users manage their own documents. Any characters entered from the keyboard at this time are interpreted as editing commands. If the entered characters are legal vi commands, vi will complete the corresponding action after accepting the user command. However, it should be noted that the entered commands are not echoed on the screen. If the characters entered are not vi commands, vi will ring the alarm.

Second: Text input mode: In the command mode, enter the command i, append the command a, open the command o, modify the command c, replace the command r or replace the command s to enter the text input mode. In this mode, any characters entered by the user are protected by vi as file content and displayed on the screen. During text input, if you want to return to command mode, just press the ESC key.

Third: Last line mode: Last line mode is also called ex escape mode. In command mode, the user presses the ":" key to enter the last line mode. At this time, vi will display a ":" on the last line of the display window (usually the last line of the screen) as the specifier of the last line mode. Wait for the user to enter a command. Most file management commands are executed in this mode (such as writing the contents of the edit buffer to a file, etc.). After the last command is executed, vi automatically returns to command mode. If you want to switch from command mode to edit mode, you can type a or i. If you need to return from text mode, just press ESC. Enter ":" in command mode to switch to last line mode, and then enter the command.

To sum up, generally when we use a command to open a file, we enter the command mode. In command mode, you can switch to text input mode and last line mode, but text input mode and last line mode cannot be switched directly to each other. Therefore, to switch text input mode to last line mode, you need to return to command mode first. Switch again and vice versa.

In addition, you can edit text in text input mode by keyboard input, or use the vi command in command mode to achieve the editing effect.

Example demonstration

First we use the command vi filename to open a file. At this time we enter the command mode

Next we Press i, then enter whatever you want on the keyboard.

Then press ESC to re-enter command mode.

In the command mode, we press: to enter the last line mode.

We enter wq!, then press Enter to force save and exit.

Next time we open the corresponding file (which can be opened with the less filename command), we will see that the content has changed.

Supplement:

(1) In the last line mode: q! [Force to exit without saving] q[Exit without saving] wq[Exit and save, you can also add one later! ]

(2) If you don’t want to save and exit directly, you can use the “ctrl+z” shortcut key in command mode or hold down the “shift” key and enter two z’s to exit.

More commands

Commands to enter vi

vi +n filename: Open the file and place the cursor at the beginning of the nth line
vi + filename: Open the file and place the cursor at the beginning of the last line
vi + /pattern filename: Open the file and place the cursor at the first string matching pattern
vi -r filename: The system crashed when editing with vi last time, restore filename
vi filename…. filename: Open multiple files and edit them in sequence

Screen scrolling commands
##Ctrl+u: Scroll half-screen to the beginning of the file

Ctrl+f: Scroll one screen to the end of the file
Ctrl+b; Scroll one screen to the beginning of the file
nz: Scroll the nth line to the top of the screen, when n is not specified Scrolls the current line to the top of the screen.

i: Before the cursor
I: At the beginning of the current line
a: After the cursor
A: At the end of the current line
o: Open a new line below the current line
O : Open a new line above the current line
r: Replace the current character
R: Replace the current character and the following characters until the ESC key is pressed
s: Start from the current cursor position and enter the Text replaces the specified number of characters
S: Delete the specified number of lines and replace them with the entered text
ncw or nCW: Modify the specified number of characters
nCC: Modify the specified number of lines

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