4 ms·

I saw that. I wasn't sufficiently confident as to whether it meant "all historical versions" or just "all current versions." If the former, then it predated p

• Normal_gaussian 10y ago
  Ah I get you. I've tried finding some source for early versions but all the links I've found are dead. It's an interesting question!
• btilly 10y ago
  Perl started with Henry Spenser's regular expression library, which was written in the mid-1980s. That got used in a lot of places, and may have been used in sed. It includes backreferences. I don't know what predates that. Perl used that as a starting place and began adding extensions such as the difference between .* and .*?. So using "non-regular thing" as a regular expression predates Perl. But the dialect we standardized on with the features people now expect is due to Perl's influence.