
Since Linux™ is a true multi-user system, the principles of both users and groups are important to the internal operation of the system, and also to the day-to-day use of the system. The way Linux™ handles users and groups makes it one of the most secure operating systems.
Existem dois tipos diferentes de usuários:
Physical Users are people who use the system physically. They have user IDs which are usually unique, as well as group IDs.
Usuários Lógicos não são vinculados a uma pessoa, mas invés disso são vinculados a uma função do sistema que são usadas por aplicativos para realizar tarefas específicas. Daemons, mail, e news são exemplos de usuários lógicos.