Because there’s non-programmers in this community, if you aren’t sure what this means but are too afraid to ask, it’s a Regular Expression that better represents the terms “Linux” and “Unix.”
Though if we’re going to be that pedantic, it would be [nN][uiI][xX]$
. That extra pipe wouldn’t actually do anything in the last example, because regexp picks one character from the set by default.
And if we want to be really pedantic,
(?!nix)[nN][uI][xX]$
Would be the most accurate.
I forget what the order of operations is, but you didn’t fuck it up. I’ve deleted the keys and started over before, though I never got secure boot to work for me in the end. Hopefully somebody smarter can provide more insight.