Automatic startup and shutdown script for Oracle databases on the Linux Platform

On most installations of the Oracle database, it is desirable to add a script for automatic startup and shutdown.
This is how to do it.
The instructions holds true for both 11g and 12c.

1. Edit the /etc/oratab file, so that the entry for your database has a Y at the end:

testdb01:/u01/oracle/product/db/112:Y

2. cd /etc/init.d

3. create a file called dbora, and add the following lines to it. Note that you should enter the name of your ORACLE_HOME path and the oracle software installation owner as values for ORA_HOME and ORA_OWNER, respectively:

#! /bin/sh 
# description: Oracle auto start-stop script.
#
# Set ORACLE_HOME to be equivalent to the $ORACLE_HOME
# from which you wish to execute dbstart and dbshut;
#
# Set ORA_OWNER to the user id of the owner of the
# Oracle database in ORACLE_HOME.

ORA_HOME=/u01/oracle/product/db/112
ORA_OWNER=oracle

case "$1" in
'start')
    # Start the Oracle databases:
    # The following command assumes that the oracle login
    # will not prompt the user for any values
    # Remove "&" if you don't want startup as a background process.
    su - $ORA_OWNER -c "$ORA_HOME/bin/dbstart $ORA_HOME" &
    touch /var/lock/subsys/dbora
    ;;

'stop')
    # Stop the Oracle databases:
    # The following command assumes that the oracle login
    # will not prompt the user for any values
    su - $ORA_OWNER -c "$ORA_HOME/bin/dbshut $ORA_HOME" &
    rm -f /var/lock/subsys/dbora
    ;;
esac

4. Set permissions:

# chgrp dba dbora
# chmod 750 dbora

5. Create symlinks to the different run level script directories:

ln -s /etc/init.d/dbora /etc/rc.d/rc0.d/K01dbora
ln -s /etc/init.d/dbora /etc/rc.d/rc3.d/S99dbora
ln -s /etc/init.d/dbora /etc/rc.d/rc5.d/S99dbora

Verify the symlinks. They should all point back to /etc/init.d/dbora

ls -la /etc/rc.d/rc0.d/K01dbora
ls -la /etc/rc.d/rc3.d/S99dbora
ls -la /etc/rc.d/rc5.d/S99dbora

What about the listener?
According to Oracle, as long as it has the default name of "LISTENER", you don't need to add it to your startup/shutdown script. If you use a different name, you must add the following line to the /etc/init.d/dbora script:

$ORACLE_HOME/bin/lsnrctl {start|stop} listener_name

The original instructions from Oracle can be found here