Check for DB status and startup DB

EXPERTS,
I need a shell script to check the DBs status (Running/Shutdown) in the server.If its Running then no issue but if it is in shutdown state ,it should prompt like " DB is shut down you want to startup??" if i enter YES it should startup.
ORACLE_SID are present in /var/opt/oracle/oratab

Atleast need a logic to implement this..