How do you set a program as a service in Linux (Debian) but have it switched off by default?

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http://unix.stackexchange.com – When you install Alfresco, it gives you an option of having it installed as a service or not. If you install it as a service, the service starts up on booting but since it's using Tomcat it's too heavy to leave as a background program. In addition, it takes a lot longer to stop than Apache. Therefore, I would like to keep it as a service but have it set to off by default so all I need to do is type sudo service alfresco start. While I can leave it set-up not as a service and write a bash script or two, I'd like to learn more about how "services" work in Linux. Apache's not a problem but it (HowTos)