I have followed Tom's Expert One on One Oracle to configure my sqlplus, I composed a file called login.sql which contains:
set serveroutput on size 1000000

set trimspool on
set long 5000
set linesize 100
set pagesize 9999
column plan_plus_exp format a80

column global_name new_value gname
set termout off
select lower(user) || '@' ||
decode(global_name, 'ORACLE10.WORLD', '10.0', 'ORA10g.WORLD',
'10g', global_name ) global_name from global_name;
set sqlprompt '&gname> '
set termout on

and then I start sqlplus, it worked well yesterday, but today the login.sql seems never been executed, because when I input the command ‘show serveroutput', it always tells me ’serveroutput off'

my database is Oracle 10g and my OS is Windows XP SP2

Thanks for any clue.