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.
Edit: based on comments, I think…
(nux|NIX)$
…would be the best. Then you don’t wind up with weird matches with things like UNiX.
Yes, but you can really only do that with single characters, since your first example is an ordered group and the second is an unordered set in a capturing group. The equivalency drops off when you include more characters.
Plus, you can do things like [a-zA-Z], and you can’t do that with the former example.
I would imagine there’s a difference in computing overhead, too, but I have no idea which is more performant.
at that point we could just flip the switch for the case insensitive mode
But then you’d match terms like “liNuX” and “UniX,” and that’s just silly. 😆
All that effort, when you could’ve just called it LUNIX.
By the way, does this expression match LUNIX? But if so, won’t it also match Binux or Bunix?
