LUbuntu16.10 install and automatically use root login (Ubuntu is similar)

Lubuntu is a new lightweight Ubuntu release that combines LXDE to make Lubuntu install, run very fast, and require low hardware resources to support X86 and ARM architecture processors.
You can download the 32bits or 64bits Lubuntu version in http://lubuntu.net/according to your computer's system. Because of the Ubuntu default installation, the root user is not given a password and the root account is not enabled. If we want to run certain commands as root, we can use the sudo command to do this.
1. Set the root password:

# sudo passwd root

Enter the root password you set twice and enable the root account. Thereafter, if you want to run the command with the root user, you can switch to Superuser using the SU command:

# su

Enter the root password you just set to use superuser privileges.
2. The above method can only use the root user for command-line operations, but the login account is still a regular account. Use the following actions to automatically log on as root and enter at the command line:

# sudo gedit/usr/share/lightdm/lightdm.conf.d/20-lubuntu.conf

(If it is Ubuntu, change the 20-lubuntu.conf to 50-ubuntu.conf)
Modify the contents of the source file to:

[seat:*]
User-session=lubuntu
autologin-user=root
greeter-show-manual-login=true

Reboot the system to complete.
3. After restarting the system, you can find that you are automatically logged in as the root user. However, the error found when Loading/root/.profile Stdin:is is not a TTY before automatic login and does not affect login. Can be modified in the following ways. Command Line Input:

# Gedit/root/.profile

(Since this is already the root account, any files in the system can be modified)
Comment MESG N, then add a row tty-s && mesg N. Restarting the system eliminates this error.

Pro-Test success.