The reason is that with sudo allows for Log on as administrator or root only in the specified command and remained in user mode. Personally, this choice does not agree at all as simply giving sudo -s to have root privileges and then "security" so sought after by turning off the root end is useless.
If we have several operations to be performed from the terminal as a system administrator or use sudo for each command as root or we lodge with the command sudo -s.
In this guide we will see how enable the root account and use the command so loved About (as to 99% of the Linux distributions) to obtain administrative privileges and how to disable it to restore the distribution as default.
Get the root account on Ubuntu is simple enough from a terminal type:
sudo passwd root
Once you enter the root password and reinserted to confirm we can access with the command on for obtaining administrative privileges. However, we can still use the command without any sudo problems.
For disable the root account and restore as default always just type in terminal:
sudo passwd -l root