This was a feature that was in the BB controller and one I wish could be implemented in the RedLine controller
It consisted of three simple text boxes where the user could create basically a macro that would be executed at program start , at tool change and at program end. Code entered in these boxes would be saved on the controller, retrieved and executed with every g-code run.
The obvious advantage is user customization of custom procedures that would run regardless of what CAD/CAM software was used to generate the g-code file.
Right now, the only means I know of to accomplish anything close to this is to modify the post-processor. That’s kind of clunky for starters, a bit foreign and very software dependent.