From 'man perlop':
If you want such a pattern to be compiled only once, add a "/o" after the trailing delimiter. This avoids expensive run-time recompilations, and is useful when the value you are interpolating won't change over the life of the script.

Same thing in camel book (3rd ed.) p.148.

In reply to Re:^4 Regex: same code works and fails, why? by Hena
in thread Regex: same code works and fails, why? by Hena

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