Add User To Root Group In Ubuntu Linux
Every Linux operating system has a built-in superuser account. In the case of Ubuntu Linux, this user account is known as root. The root user is also a member of a Supplementary group root.
What happens if you add a normal user to the root group?
We can add other users to the root group using the usermod command:
usermod -aG root sysadmin
You would expect sysadmin to have unlimited privileges to the Ubuntu system since he is now a member of the root group. But the answer is NO, the user will not get administrative privileges.
As you can see the sysadmin user does not have administrative privileges. Ubuntu prevent this as a security measure, otherwise it gives unlimited privileges to the normal user.
Granting privileges using sudoers is the preferred method in Ubuntu Linux.