The script will give you an report of the status of you RMAN running backup, you will get the start time ,
actual time size and amount of work done so far.
select to_char(start_time,'hh24:mi:ss') Start_Time,
to_char(sysdate,'hh24:mi:ss') Time_Now,
totalwork sofar,
(sofar / totalwork) * 100 pct_done
from v$session_longops
where totalwork > sofar
AND opname NOT LIKE '%aggregate%'
AND opname like 'RMAN%';