Script to find active sessions in database - oracle database script

SET echo OFF
SET linesize 95
SET head ON
SET feedback ON col sid head "Sid" form 9999 trunc col serial# form 99999 trunc head "Ser#" col username form a8 trunc col osuser form a7 trunc col machine form a20 trunc head "Client|Machine" col program form a15 trunc head "Client|Program" col login form a11 col "last call" form 9999999 trunc head "Last Call|In Secs" col status form a6 trunc
SELECT sid,
       serial#,
       substr(username, 1, 10) username,
       substr(osuser, 1, 10) osuser,
       substr(program||MODULE, 1, 15) program,
       substr(machine, 1, 22) machine,
       to_char(logon_time, 'ddMon hh24:mi') login,
       last_call_et "last call",
       status
FROM gv$session
WHERE status='ACTIVE'
ORDER BY 1 /