1. Create a group of WebDev:
Example: GroupAdd WebDev
2. Create a user and add the user to the WebDev group:
Example: adduser Xuys -g WebDev
Give the user password:
Example: Passwd Xuys
3. Add a user to the root group:
Example: usermod -g root xuys
4, completely delete a user:
Example: Userdel -r Xuys
