Ref –> Linux Login as Superuser (root user)
How to become superuser in Linux
Let us see some examples of the su and sudo command to become superuser in Linux.
Become a superuser in Linux using sudo command
You must be part of special secondary group on Linux:
sudo group on a Debian or Ubuntu Linux
wheel group on a CentOS/RHEL/Fedora/Oracle Linux
You can see your secondary group membership by running either groups command or id command
$ groups
$ id
Next run the following command to become a root/super user:
$ sudo -i
When promoted type your password to gain root shell
and when need to logout use
$ exit