Vim's TAB key

The default tab key in Vim is approximately 6 spaces (visual) width. If you want to change to 4 spaces, use the following command:
Shiftwidth=4
Softtabstop-4
The meaning of Shiftwidth is: when you need to indent after enter, indent a few spaces, the default is 6. In this change to 4, so that the TAB key is the same.
Softtabstop means: Press the TAB key after indentation, press BACKSPACE (BACKSPACE) back a few spaces, the default is 6. Through the above two changes in the command, whether it is a carriage return or TAB has maintained a consistent 4 spaces, more in line with the expectations of everyone.

Vim's TAB key