Create a file listing applications, processes, and services running and those scheduled to run on OSX on boot

I'm looking for a script or some advice on how to write a script that can create a file listing all of the processes that run when my system boots. I suspect that this goes beyond just waiting till the boot process is complete and enumerating t开发者_高级运维he applications and services that are currently running.

The idea is to create a file listing all things that ran, are running, or will run and compare that file to a new one on each boot so I can raise an alert when something has changed.