
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.
Terdapat dua jenis pengguna:
Physical Users are people who use the system physically. They have user IDs which are usually unique, as well as group IDs.
Pengguna Logikal tidak bergantung kepada individu, tetapi bergantung kepada fungsi sistem yang digunakan oleh aplikasi untuk membuat tugas khusus. Daemon, mel, dan berita adalah contoh pengguna logikal.