How to check the configuration of rman?

By default the RMAN configuration is stored in the control file. You can see the default values
for the configuration parameters by using RMAN to connect to the database and issuing the SHOW ALL command.
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Check  RMAN configuration
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[oracle@wasiq d01]$ rman

Recovery Manager: Release 11.2.0.1.0 - Production on Fri Dec 27 21:43:39 2013

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RMAN>
RMAN> connect target /;

connected to target database: PROD (DBID=246965557)
using target database control file instead of recovery catalog

RMAN> show all;

RMAN configuration parameters for database with db_unique_name PROD are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE COMPRESSION ALGORITHM 'BASIC' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE ; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/d01/oracle/product/11.2.0/dbs/snapcf_prod.f'; # default

RMAN>