how would I do this ? e.g. assume my keyword input file would look like this

Something along these lines:

my @patterns = map { chomp; qr/\b\Q$_\E\b/ } <$filehandle>;

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Is there a more efficient way of doing the regex?

There are various trade-offs; as long as you have few and simple patterns, combining them is more likely to slow things down than speed them up, because a combined pattern will cause the engine to waste a lot of effort backtracking to check alternatives. study has never been of any use to me, either. If you have a lot of patterns, you may want to look into Regexp::Assemble as a way of combining them.

Makeshifts last the longest.

In reply to Re: speeding up a regex by Aristotle
in thread speeding up a regex by Anonymous Monk

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