Restrict root only in a safe landing terminal
(1) vi to edit the file / etc / securetty configuration file, comment out the ban
(2) prohibit root user login from the terminal
Editor: vi / etc / securetty
Will be added in front of the terminal like a #
Ordinary users are prohibited
After the touch / etc / nologin ordinary users can not log in directly to the lift, then delete the file nologin