1. First export the following variables :
export OB2APPNAME=<SID>
export OB2BARLIST=<Backup barlist>
2. Now run the ob2rman.pl script as in the following example :
/opt/omni/lbin/ob2rman.pl -restore_catalog -session 2016/01/29-1 -apphost systema.usa.hp.com
[Normal] From: ob2rman@systema.usa.hp.com "QDB" Time: 02/23/16 04:04:12
Starting restore of target database.
[Normal] From: ob2rman@systema.usa.hp.com "QDB" Time: 02/23/16 04:04:13
Starting restore of recovery catalog.
[Normal] From: ob2rman@systema.usa.hp.com "QDB" Time: 02/23/16 04:05:16
Starting Oracle Import utility.
[Normal] From: ob2rman@systema.usa.hp.com "QDB" Time: 02/23/16 04:06:23
Oracle Import utility completed.
[Normal] From: ob2rman@systema.usa.hp.com "QDB" Time: 02/23/16 04:06:39
Restore of recovery catalog completed.
[Normal] From: ob2rman@systema.usa.hp.com "QDB" Time: 02/23/16 04:06:40
Restore of target database completed.