The qtemp script will show the used and free temp file blocks, who is using the temp blocks and the details of the temp files.

SQL

prompt###Temp segment status
select TABLESPACE_NAME,TOTAL_BLOCKS,USED_BLOCKS,FREE_BLOCKS from v$sort_segment;

col file_name format a65
prompt###Who is using the temp segments
SELECT b.tablespace, b.segfile#, b.segblk#, b.blocks, a.sid, a.serial#,
a.username, a.osuser, a.status, b.sqlhash
FROM v$session a,v$sort_usage b
WHERE a.saddr = b.session_addr
ORDER BY b.tablespace, b.segfile#, b.segblk#, b.blocks;

prompt###Temp Tablespace details
Select tablespace_name, file_name, bytes/1024/1024 MB from dba_temp_files;

Output