set lines 130
set pages 2000
col file_name for a50
break on tablespace_name

select tablespace_name, file_name
from dba_data_files ddf ,
(
select substr(file_name,16) sstr
from dba_data_files
group by substr(file_name,16)
having count(substr( file_name ,16))> 1
) dup
where instr(ddf.file_name, dup.sstr) > 0;

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