SuperUser

A superuser is a user account that has unrestricted rights to a computer system. In Unix-like operating systems, the superuser commonly called root, has UID 0 and can read and modify any file, alter system configuration, and manage all users. In Windows, the closest equivalent is an Administrator account that can elevate privileges for system-wide changes, often via User Account Control prompts.

A superuser can perform tasks such as installing and removing software, changing network settings, configuring security policies, creating and deleting user accounts, and accessing files regardless of standard permissions. This level of access is powerful and also risky, so the use of a superuser account is typically restricted to tasks that require full control of the system.

Privilege management is a central aspect of operating system design. On Unix-like systems, regular users may perform elevated tasks using tools such as sudo or su to switch to root, with the sudoers configuration determining who may elevate and for how long. On Windows, elevation is requested at runtime through mechanisms like UAC, and administrators may use separate admin accounts or remote management tools to minimize exposure.

Security considerations are critical because the superuser can cause extensive damage or data loss if misused or compromised. Best practices include following the principle of least privilege, avoiding permanent login as a superuser for day-to-day tasks, using temporary elevation when needed, enforcing strong authentication, and auditing privileged activity.

The term is also used as the name of the Super User Stack Exchange site, a question-and-answer community focused on computer software and hardware.