do you prefer this:
SQL>
or this:
sys@orcl(281)>
This format helps you to find your session id immediately. it could be helpful when you want to kill the session or when there are multi databases on same OS.
first of all we have to add this line in /home/orac.le/.bash_profile
export ORACLE_PATH=/u01/app/oracle/sql/
then create a file like login.sql in directory : /u01/app/oracle/sql/
define _editor=vi
set serveroutput on size 1000000
set trimspool on
set long 5000
set linesize 200
set pagesize 9999
set timing on
column plan_plus_exp format a80
column global_name new_value gname
set termout off
define gname=idle
column global_name new_value gname
select lower(user) || '@' || lower(substr( global_name, 1, decode( dot, 0, length(global_name),dot-1) )) || '(' || sys_context('userenv', 'sid') || ')' global_name
from (select global_name, instr(global_name,'.') dot
from global_name ) a
/
set sqlprompt '&gname> '
set termout on
give it a try.