So make's default behaviour "make somefile.csv" is to build the whole tree of dependencies. To force rebuild of everything, run "make -B somefile.csv". It then assumes everything is out of date.

To force rebuild of one step, just delete its output or run "touch" on one of its dependencies before running make. Then that step will get redone.

I like to have generated data in a separate folder, say "output/" which you can then snapshot, blow away, or do what you like with. Basically though, I keep it separate from data and code inputs.