Can I use an RMAN Backup of DB1 to replace DB2 I have a backup of an Oracle 11g database on Linux, that is a version that is 'prescrub' needed by other users.  This is for an ACTIVE database that is now scrubbed, so I do not want to use it as the 'active' database for the clone.

I have a second database that is no longer needed, to which I want to overwrite with the 'prescrub' backup of DB1.  Can I restore the PRESCRUB backup of DB1 over DB2?  If so, what are the appropriate commands or modifications needed?
Sure you can, you can duplicate a database using RMAN backups. For example:


shut down DB2
delete all datafiles, redo logs, controlfiles of DB2
start DB2 in NOMOUNT
with RMAN, connect to DB1 as target, DB2 as auxiliary:

rman target sys/password@DB1 auxiliary /

duplicate the database until the required time, and rename files on the fly (if required), for example::

duplicate database to db2
until time "to_date('2016-02-20 16:00:00', 'YYYY-MM-DD HH24:MI:SS')"
db_file_name_convert (/oradata/DB1, /oradata/DB2)
logfile
'/oradata/DB2/redo01.log' SIZE 50M,
'/oradata/DB2/redo02.log' SIZE 50M,
'/oradata/DB2/redo03.log' SIZE 50M;