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.
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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.
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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.