Modify the default shell

1. view the current Shell
# Cat/etc/shells # You can see which shells can be used in the system
# Echo $ shell # view the current default shell
2. Why is no history prompt displayed when I press the up/down key?
The current shell is not/bin/bash
3. modify the current Shell
Command: CHSH-S/bin/sh user name (if the user name is not added, it indicates the current user)
4. Where has CHSH-s been modified?
CHSH-s actually modifies the line corresponding to your user name in the/etc/passwd file.

PS: After the path is changed to shell, logout is required to take effect.