Shrink TEMP Tablespace using alter tablespace command
SQL> ALTER TABLESPACE temp SHRINK SPACE KEEP 50M;.

Shrink TEMPFILE using alter tablespace command
SQL> ALTER TABLESPACE temp SHRINK TEMPFILE '/u01/app/oracle/oradata/TEST11G/temp01.dbf' KEEP 40M;

Shrink TEMP Tablespace to the smallest possible size:
SQL> ALTER TABLESPACE temp SHRINK SPACE;

SELECT pid FROM v$process
WHERE addr =
(
SELECT paddr FROM v$bgprocess
WHERE name = 'SMON'
);

ORADEBUG WAKEUP 6