NIS Maps

NIS maps are databases that specify certain system information such as user names, passwords, and host names, in a database format called DBM (Database Management).

Each map is constructed from a standard text file by associating an index key with a value. For example, the information in the master server's /etc/hosts file is used to create a map that uses each host name as a key, and the IP address as the value. The key and value pairs (also known as records) that are created from the entries in the/etc/hosts file comprise the hosts.byname map.

The most commonly used maps have nicknames that some commands can translate into map names. For instance, when you enter:

ypcat hosts

The output you receive is actually the contents of the hosts.byname map, because there is no map called hosts in the NIS database. (The ypcat -x command produces a list of available nicknames.)

By default, the maps listed in the following table are created if their corresponding files are available on the master server: