A directory is a hierarchical structure that stores information about objects on the network. A directory service, such as Active Directory Domain Services (AD DS), provides the methods for storing directory data and making this data available to network users and administrators. For example, AD DS stores information about user accounts, such as names, passwords, phone numbers, and so on, and enables other authorized users on the same network to access this information.
LDAP stands for “Lightweight Directory Access Protocol”. It is a simplification of the X.500 Directory Access Protocol (DAP) used to access directory information. A directory is essentially a special-purpose database optimized to handle identity-related information.
Bash provides one-dimensional array variables. Any variable can be used as an array; the declare builtin will explicitly declare an array. There is no maximum limit on the size of an array, nor any requirement that members be indexed or assigned contiguously. Arrays are zero-based.