As part of its implementation, the RPM software maintains a database on the system of all packages that have been installed, and documenting which files those packages have installed on the system. RPM is designed to be queried easily, making it possible for you to search this database to determine what applications have been installed on the system and to see which packages have supplied each file on the system. This feature makes RPM-based systems extremely easy to use, since a single RPM command can be used to view all installed applications on the system.