How to backup particular tablespace in rman?

[oracle@wasiq ~]$ rman

Recovery Manager: Release 11.2.0.1.0 - Production on Fri Jan 10 21:21:53 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 tablespace users;

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=197 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00005 name=/d01/oracle/oradata/prod/users02.dbf
input datafile file number=00004 name=/d01/oracle/oradata/prod/users01.dbf
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_nnndf_TAG20140110T212207_9f05s767_.bkp tag=TAG20140110T212207 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 10-JAN-14

RMAN>