What is a uid?

A UID (User ID) is a unique identifier assigned to each user in a computer system or network. It is used to distinguish between different users and manage access and permissions to various resources and services. UIDs are typically assigned by the operating system or application when a user account is created.

UIDs are commonly used for security and access control purposes, as they help ensure that each user can only access the resources they are authorized to use. They are also used for tracking user activity, monitoring system performance, and managing user preferences and settings.

In Unix-based systems, UIDs are numerical values that are associated with each user account. Each UID is unique within the system, and is used in conjunction with the user's username to identify and authenticate them. Additionally, there is also a corresponding UID for group identification (GID), which is used to assign users to specific groups for shared access to resources.