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.

What is UID in Linux?

A UID (user identifier) is a number assigned by Linux to each user on the system. This number is used to identify the user to the system and to determine which system resources the user can access. UID 0 (zero) is reserved for the root. … UID 10000+ are used for user accounts.

What is UID and GID Linux?

What are Uid and Gid? As you might expect, uid is a number associated with a user account and gid is a number associated with a group. The root user and group are usually given uid and gid 0. … For example, uid and gid values help your Linux systems differentiate between root and a user with lower privileges.