script to kill all session in oracle

oracle-kill-all-session.sql

BEGIN
  FOR R IN (
  SELECT
    SID,
    SERIAL#
  FROM V$SESSION
  WHERE USERNAME IS NOT NULL AND SID <> (
    SELECT sys_context('USERENV', 'SID')
    FROM DUAL))
  LOOP EXECUTE IMMEDIATE 'ALTER SYSTEM KILL SESSION ''' || R.SID || ',' || R.SERIAL# || '''';
  END LOOP;
END;

DISCONNECT