How to backup of spfile?

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How to backup of spfile?
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[oracle@wasiq ~]$ rman

Recovery Manager: Release 11.2.0.1.0 - Production on Fri Jan 10 21:16:13 2014

Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

RMAN> connect target /;

connected to target database: PROD (DBID=246965557)

RMAN> backup spfile;

Starting backup at 10-JAN-14
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=71 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current SPFILE in backup set
channel ORA_DISK_1: starting piece 1 at 10-JAN-14
channel ORA_DISK_1: finished piece 1 at 10-JAN-14
piece handle=/d01/oracle/flash_recovery_area/PROD/backupset/2014_01_10/o1_mf_nnsnf_TAG20140110T211622_9f05ggz1_.bkp tag=TAG20140110T211622 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 10-JAN-14

Starting Control File and SPFILE Autobackup at 10-JAN-14
piece handle=/d01/oracle/product/11.2.0/dbs/cfc-246965557-20140110-03 comment=NONE
Finished Control File and SPFILE Autobackup at 10-JAN-14

RMAN>