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  • Thanks, I like the perl solution. It appears to be within a factor of 2 of the speed of grep, which is faster than sed/python/gawk solutions. Is there a simple way to extend it to do the equivalent of egrep "pattern1|pattern2|pattern3"? Commented Jun 13, 2018 at 18:35
  • @dshin, Perl regexes are pretty much an extension of extended regexes like what grep -E uses, so this|that works out of the box. (see this question and Perl's docs for details) Commented Jun 13, 2018 at 18:39
  • @dshin, also, since you're aiming for speed, you could try if replacing the second regex with ... && substr($_, -1, 1) eq "\n"' would be faster. Commented Jun 13, 2018 at 18:42
  • Hm, your original actually is clocking in slightly faster for me, but they are very close. Commented Jun 13, 2018 at 18:44
  • @dshin, allright, just goes to show that Perl's regex processing is pretty well optimized Commented Jun 13, 2018 at 18:49