
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.
Postoje dvije različite vrste korisnika:
Physical Users are people who use the system physically. They have user IDs which are usually unique, as well as group IDs.
Logical Users nisu vezani za osobu, nego za sistemske funkcije koje koriste aplikacije za određene radnje. Elektronska pošta je tipičan primjer logičkog korisnika.