EXEC dbms_monitor.SESSION_TRACE_ENABLE(session_id =>27, serial_num => 60, waits => TRUE, binds =>FALSE);
EXEC dbms_monitor.SESSION_TRACE_DISABLE(session_id=> 27, serial_num => 60);

--12C  -- Windows \ backward slash
select b.sid, b.serial#, b.username, c.value || '/' || instance || '_ora_' ||
  ltrim(to_char(to_number(a.spid),'fm99999')) || '.trc'
  from v$process a, v$session b, v$parameter c, v$thread c
  where a.addr = b.paddr
   and (b.sid = 606 or b.username = 'USERNAME')
  and c.name = 'user_dump_dest' ;
  
--12C  -- Linux / forward slash
select b.sid, b.serial#, b.username, c.value || '\' || instance || '_ora_' ||
  ltrim(to_char(to_number(a.spid),'fm99999')) || '.trc' Trcfile_Location
  from v$process a, v$session b, V$DIAG_INFO c, v$thread c
  where a.addr = b.paddr
   and (b.sid = 606 or b.username = 'USERNAME')
  and c.NAME = 'Diag Trace';