So I started to work it out, only to discover the link about the problem in the article gives it away - counterfactuals can be used, so might as well read that instead of any thing I come up with. And thus I just wasted a bunch of time trying to figure out which specific one worked (now erased) ... but my hunch was correct! (Although hunches are hardly proofs, tsk tsk)

Also, I want to thank you again for helping me out with awk/sed/grep/command line stuff, from a year ago!