programs not in root

I am making a program that needs to access many other files in order to function properly. I want this to be able to be placed in any directory on the system and have the main file access the other files relative to where it currently is. Ideally, I would want a command to return the main program's directory without using the search API or the local directiry. Keep in mind that the programs local directory may change many times throughout the program. Any help would be nice!

You may be looking for shell.getRunningProgram(). You explenation isn't very clear though, how can the running directory change?

Thanks for your help! this is what the solution was:
fs.getDir(shell.getRunningProgram())