Directory

A directory is a container within a computer's file system that groups files and other directories. It forms a hierarchical tree and is represented by a special file that records the entries it contains, along with metadata such as creation and modification times, size, and access permissions.

In most operating systems, the topmost directory is the root. Paths describe locations, such as /home/user or C:\Users\Alice. Directories themselves are not data files but repositories of files and subdirectories. Access to a directory is controlled by permissions; users may list, create, rename, move, or delete entries depending on rights. Unix-like systems typically require execute permission on directories to access their contents; Windows uses access control lists to govern visibility and modification rights.

The term directory is also used for lists of people or resources, such as a telephone directory, an employee directory, or an online business directory. In computing networks, directory services (for example LDAP or Active Directory) store information about users, groups, computers, and services to enable authentication, authorization, and resource discovery.

Structure tends to be hierarchical, though some file systems allow multiple roots or non-tree links. Large directories may rely on indexing, caching, and journaling to improve performance and reliability. Regular maintenance includes backup, integrity checks, and, in dynamic environments, synchronization with other systems.