connect to idle instance during to tailing "/" in string of ORACLE_HOME

database was strarted by dbstart with below content in /etc/oratab
#no tailing "/" in it
udk:/oracle/product/10.2.0:Y

udk1:/oracle> echo $ORACLE_HOME
/oracle/product/10.2.0/

udk1:/oracle> echo $ORACLE_SID
udk
udk1:/oracle> sqlplus / as sysdba

SQL*Plus: Release 10.2.0.5.0 - Production on Mon Mar 10 13:36:02 2014

Copyright (c) 1982, 2010, Oracle.  All Rights Reserved.

Connected to an idle instance.

SQL> exit
Disconnected


udk1:/oracle> export  ORACLE_HOME=/oracle/product/10.2.0
udk1:/oracle> sqlplus / as sysdba                      

SQL*Plus: Release 10.2.0.5.0 - Production on Mon Mar 10 13:36:22 2014

Copyright (c) 1982, 2010, Oracle.  All Rights Reserved.


Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> exit