Modular scripts

Not sure how to really phrase the question so I will explain what I am doing:

I need to allow users to perform some "system" commands, that is, Rails will execute these commands. In order to parse the return data and display it in a certain way, I need to store each of the allowed "commands" in its own script. Where should these scripts go? Should it be a module? Should it open the directory and read in all module files? How would I get the class name? etc.

I've never done this before so I'm just needing some direction on this.