List Active Oracle Sessions

SELECT
       substr(a.spid,1,9) pid,
       substr(b.sid,1,5) sid,
       substr(b.serial#,1,5) ser#,
       substr(b.machine,1,6) box,
       substr(b.username,1,10) username,
--       b.server,
       substr(b.osuser,1,8) os_user,
       substr(b.program,1,30) program
FROM v$session b, v$process a
WHERE
b.paddr = a.addr AND b.STATUS='ACTIVE'
AND TYPE='USER'
ORDER BY spid;