How to get the extent information in oracle

Query:
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set pages 3000 lines 300
col owner for a15
col segment_name for a30
col TABLESPACE_NAME for a30
select OWNER,SEGMENT_NAME,TABLESPACE_NAME,EXTENT_ID,FILE_ID,BYTES/1024 from dba_extents where OWNER='&OWNER' and SEGMENT_NAME='&SEGMENT_NAME' order by EXTENT_ID;