One problem tho, the following all match the string "\n": 
/.*/
/\z/
/.{0}\z/

[download]
It's possible that \z is meant to introduce some specialness when combined with .* (or possibly some other quantifiers), but I haven't seen it mentioned in any docs. This is either a bug, or a very poorly documented feature.

In reply to Re^3: Strange regex to test for newlines: /.*\z/ by Mutant
in thread Strange regex to test for newlines: /.*\z/ by betterworld

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