vi has two modes: one is editing and the other is command. We enter the edit from the command as: i, o, a. I generally use i: because I am most familiar with this. Exit and click the esc key to enter command mode.
We need to delete the current and next line of the file. The command is: 2dd. Generally, we use a single character to delete it as: x. We usually enter the editing mode to add, modify and delete.
However, when we delete and modify too much, we use the command line mode to modify it, which is convenient and fast. In the command line, the four commands x, dd, u, and p are most commonly used:
x: Delete the current character;
dd: Delete the current line;
u:Restore the previous operation;
p: Copy the previously deleted row.
vi is a commonly used editor under Linux terminal or console. The basic operation method is: vi/path/file name
For example, vi /etc/saikik means displaying the contents of the /etc/saikik file. Use the Page Up and Page Down keys on the keyboard to turn up and down; press the Insert key and you can see that there is the word "Insert" in the lower left corner of the window, indicating that the current insertion editing state. At this time, the content entered from the keyboard will be inserted into the cursor position; press the Insert key, and the word "Replace" in the lower left corner will be the word "Replace" in the lower left corner, indicating that the current replacement editing state. At this time, the content entered from the keyboard will be replaced in the cursor position. After editing the content, press the Esc key, enter ":wq", and press Enter to save and exit.
If you do not want to save and exit directly, press the Esc key, enter ":q!" and press Enter. "wq" means Write and Quit, that is, save and exit; "q!" means to force exit by ignoring modification.