How to open an Oracle Standby database for READ ONLY mode

When you have an Oracle Standby Database sometimes you need to put it in READ ONLY mode for what ever the reason would be. To put the Standby database in READ ONLY mode you need to stop the Recover process and alter it's state to READ ONLY by using the following commands.

sqlplus /as sysdba
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
alter database open read only;

sqlplus /as sysdba
shutdown immediate;
startup mount;
alter database recover managed standby database until cancel;