I use this PHP script to automate running multiple jobs hourly, daily, weekly and monthly. Sure you can create simple scripts for each job and run them all separately via a Unix crontab, but this self-contained script allows running unlimited jobs all from one file. Plus, it provides a framework for building jobs and storing configurations after each run. It creates a cache file .crontab.php in the same directory, to store runtime and configuration data.
This version has been customized to run under ZenCart. Place in the ZenCart admin directory and make the modification to admin/includes/application_top.php as directed. To run automatically add to your system’s local crontab.
I am currently using to run order shipped updates and custom inventory re-order warnings on ZenCart sites. If you are interested in these specific jobs contact me for details.