How to Add User to Sudoers in Debian
The sudoers file contains a set of rules that determines which users or groups are granted with sudo privileges as well as the level of the privileges.
Su Command in Linux (Switch User)
The su (short for substitute or switch user) command allows you to run commands with another user's privileges, by default the root user.
How to Add User to Sudoers in Ubuntu
On Ubuntu, the easiest way to grant sudo privileges to a user is by adding the user to the sudo group. Members of this group will be able to execute any command as root via sudo.
How to Add User to Sudoers in CentOS
In CentOS you have two options to grant sudo access to a user. The first one is to add the user to the sudoers file. The second option is to add the user to the wheel group.