This is the most insecure thing you can do to your linux system. That said however, when working on development systems at home I like to logon as SSH. Granted this is behind a firewall to a linux system with no access from the internet.
This was tested on Ubuntu 14.x on a Raspberry Pi.
I do this out of laziness. NEVER do this to an internet accessible system.
First change/set root’s password:
sudo passwd root
and comment out the following line by adding a # in front of it:
Then add the following line:
service ssh restart
Now you should be able to remotely SSH into your system as root.