Oerr is an Oracle utility that extracts error messages with recommended actions from the standard Oracle message files.
Example:
$ oerr ORA 23419
23419, 00000, "regenerate replication support before resuming master activity"
// *Cause: There are tables in the object group that require regeneration
// of replication support.
// *Action: Check the generation_status column in the all_repobjects view.
// Regenerate replication support for any table in the object group
// with a 'NEEDSGEN' status. Resume master activity.
//