rdist takes a list of files, compares the modification dates and times of those files on the local host with the modification dates and times of those files on the remote host, and updates the remote files only if the modification times differ. rdist also has features that let you define alternate rules and exceptions to rules. rdist preserves the access permissions and modification times of files it distributes. rdist is usually used with a distribution file, called distfile, that contains a set of rules for determining which files should be updated on which hosts.