Create a file that lists the applications, processes, and services that are running and running on OSX at boot time.

I am looking for a script or some advice on how to write a script that can create a file that lists all the processes that start when my system boots. I suspect that this goes beyond just waiting for the download process to complete and listing the applications and services that are currently running.

The idea is to create a file that lists all running, running or running, and compare this file with a new one at each boot so that I can raise a warning when something changes.