I forget whether this is the second or third time I've managed to brick a workstation by dutifully following instructions from the "experts." But at least one person's directions are worth the bytes: [Linux] PHP not working in userdir (public_html).
I'd love to say thank you on devPlant's website, but--ironically enough--PHP seems to be borked there. But at least once the workstation is un-bricked, I know why the the LAMP upgrade borked my development website, and how to fix it for real next time.
In any case, I just thought that the person(s) behind devPlant deserved a shout-out for sharing what they know, and saving me from re-bricking that PC.