SET ECHO ON and SET SERVEROUTPUT ON

This was tested on Oracle 9. When you login to SQL*Plus, the default for ECHO and SERVEROUTPUT is OFF. If you SET them both to ON and reconnect to SQL*Plus, ECHO stays ON but SERVEROUTPUT reverts to OFF:

ORACLE9 > sqlplus /

SQL*Plus: Release 9.2.0.7.0 - Production on Mon Jul 2 17:48:08 2012

Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.

Connected to:

Oracle9i Enterprise Edition Release 9.2.0.7.0 - Production

With the Partitioning option

JServer Release 9.2.0.7.0 - Production

SQL> show echo

echo OFF

SQL> show serveroutput

serveroutput OFF

SQL> set echo on

SQL> set serveroutput on

SQL> show echo

echo ON

SQL> show serveroutput

serveroutput ON size 2000 format WORD_WRAPPED

SQL> conn /

Connected.

SQL> show echo

echo ON

SQL> show serveroutput

serveroutput OFF

SQL>