Reference: How to pass password to mysql command line

I want to grab returned metadata from an AWS EC2 instance and set a new mysql password based on this data.

I need assistance with the script which will run as first boot.

#!/bin/bash  
ec2metadata --instance-id; Need to store echoed response.   
mysql -u root -pOldPassword  
UPDATE mysql.user  

Now pass instance-id and use it to set new password for mysql root.

SET authentication_string = PASSWORD('instance-id'), password_expired = 'N'
WHERE User = 'root' AND Host = 'localhost';

FLUSH PRIVILEGES;

EXIT