Automate EC2 Instance Setup with user-data Scripts - Alestic.com: "user-data Scripts
The Ubuntu and Debian EC2 images published on http://alestic.com allow you to send in a startup script using the EC2 user-data parameter when you run a new instance. This functionality is useful for automating the installation and configuration of software on EC2 instances.
The basic rule followed by the image is:
If the instance user-data starts with the two characters #! then the instance runs it as the root user on the first boot.
The “user-data script” is run late in the startup process, so you can assume that networking and other system services are functional.
"
'via Blog this'
