How do I safely replace brew on Big Sur?
I'm still trying to solve my problem with installing Ruby on a new Mac, and some discussions are saying that I need to reinstall
brew because of the change from the old chipset to the M1. (I'm just repeating what I've heard; I don't understand the issue.) I'm willing to try this, but it looks like uninstalling
brew also removes everything I installed with it, and that would be bad if I can't assemble a manifest and reinstall everything after.
How do I safely replace
Specifics: My new machine is an M1 Mac running Big Sur. I used Migration Assistant to move data from my previous machine, which was running Sierra. This migration carried along the old version of
brew, which apparently is not the version Big Sur wants.
First question: can I get a list of "top-level" things I've installed with
brew? I see that
brew list shows me a long list of packages, many of which I didn't explicitly install but are presumably dependencies installed on my behalf. If I'm going to have to reinstall stuff after I uninstall and reinstall
brew, I'd like to be able to figure out what I specified before I nuke anything. Or should I just save that list and feed it all to
brew install after the replacement, and let duplicate dependencies and obsolete packages sort themselves out?
Second question: what else could go wrong that I should anticipate and defend against? "Back everything up" isn't the complete solution I thought it was; I recently discovered (the hard way) that Time Machine doesn't back up everything on the disk, because apparently MacOS thinks that some files should be hidden from users.
I've seen posts that recommend installing the new
brew alongside the old one and then changing some paths and other environment variables, but it sounds confusing.