Script to check free space and used space in Oracle Database tablespaces

select a.tablespace_name,
       a.bytes_alloc/(1024*1024) "TOTAL ALLOC (MB)",
 a.physical_bytes/(1024*1024) "TOTAL PHYS ALLOC (MB)",
       nvl(b.tot_used,0)/(1024*1024) "USED (MB)",
       (nvl(b.tot_used,0)/a.bytes_alloc)*100 "% USED"
from ( select tablespace_name,
       sum(bytes) physical_bytes,
sum(decode(autoextensible,'NO',bytes,'YES',maxbytes)) bytes_alloc
       from dba_data_files
       group by tablespace_name ) a,
     ( select tablespace_name, sum(bytes) tot_used
       from dba_segments
group by tablespace_name ) b
where a.tablespace_name = b.tablespace_name (+)
--and   (nvl(b.tot_used,0)/a.bytes_alloc)*100 > 10
and   a.tablespace_name not in (select distinct tablespace_name from dba_temp_files)
and   a.tablespace_name not like 'UNDO%'
order by 1
 --order by 5
/ 

RMAN-03009: failure of allocate command on ORA_AUX_SBT_TAPE_1 channel

This is an error during Database Clone using RMAN. I was trying to restore database using RMAN Backup 

RMAN-00571: ===========================================================

RMAN-00569: ===============
ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-03002: failure of Duplicate Db command
RMAN-05501: aborting duplication of target database

RMAN-03009: failure of allocate command on ORA_AUX_SBT_TAPE_1 channel 
ORA-19554: error allocating device, device type: SBT_TAPE, device name:

ORA-27211: Failed to load Media Management Library

Additional information: 

Cause: Backup Configuration was modified.

Solution:
Use the below command to Resolve the error and continue with Database Restore

rman auxiliary / 
run
{
allocate auxiliary channel c1 type disk;
allocate auxiliary channel c2 type disk;
duplicate database to 'DEV' backup location '/Daily_Backup/Backup_16042018';
}
exit;
EOF