Back Identificador d'usuari Catalan Identifikátor uživatele Czech Benutzerkennung German Identificador de usuario Spanish User identifier French User identifier Italian ユーザー識別子 Japanese 사용자 식별자 Korean Brukeridentifaktor NB UID Polish
Unix-like operating systems identify a user by a value called a user identifier, often abbreviated to user ID or UID. The UID, along with the group identifier (GID) and other access control criteria, is used to determine which system resources a user can access. The password file maps textual user names to UIDs. UIDs are stored in the inodes of the Unix file system, running processes, tar archives, and the now-obsolete Network Information Service. In POSIX-compliant environments, the shell command id gives the current user's UID, as well as more information such as the user name, primary user group and group identifier (GID).