
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.
Obstajata dve različni vrsti uporabnikov:
Physical Users are people who use the system physically. They have user IDs which are usually unique, as well as group IDs.
Logični uporabniki niso povezani z osebo, ampak so povezani s sistemsko funkcijo, ki jo uporabljajo programi za opravljanje določenih nalog. Ozadnje opravilo, pošta in novice so primeri logičnih uporabnikov.