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.

//