Journal files are automatically created by named when changes are made to dynamic zones (e.g., by nsupdate). They record each addition or deletion of a resource record, in binary format, allowing the changes to be re-applied to the zone when the server is restarted after a shutdown or crash. By default, the name of the journal file is formed by appending the extension .jnl to the name of the corresponding zone file.
named-journalprint converts the contents of a given journal file into a human-readable text format. Each line begins with "add" or "del", to indicate whether the record was added or deleted, and continues with the resource record in master-file format.