Automating Database Startup and Shutdown Script

Edit the "/etc/oratab" file and change the last character to 'Y' for each instance you want to auto-start:
Enter the required information (ORACLE_HOME and ORACLE_OWNER), and click "GO" to generate the codes. Then create a file called "/etc/init.d/dbora" as the root user, copy/paste the codes in "shell script". Then make it executable:
chmod 750 /etc/init.d/dbora
and create the symbolic links for the /etc/rc[0-6].d directories:
chkconfig --add dbora