System Administration Guide, Volume 1

Becoming Superuser (root)

Most administrative tasks such as adding users require that you log in as root (UID=0) first. The root account is also known as the superuser account because it's used to make system changes and can override user file protection in emergency situations.

The superuser account should be used only to perform administrative tasks to prevent indiscriminate changes to the system.

You can either log into the system as superuser or use the su(1M) command to change to the superuser account.

If you are using role-based access control, you must assume a role (either superuser or some other role) to perform administrative tasks. Roles are assumed by using the su command; you cannot log in to a role directly. See "Role-Based Access Control" in System Administration Guide, Volume 2 for more information.

How to Become Superuser (root)

Become superuser by one of the following methods. Both methods require that you know the root password.