In addition to the above good tips, there is a talk by Nicholas Clark (from 2005), "When Perl is not quite fast enough", that explores some other things you can do to make your code a bit faster.

But in general, the best optimizations are by optimizing the algorithm, and also first finding out what exactly the slow parts are before you start optimizing.

In reply to Re^4: Need to speed up many regex substitutions and somehow make them a here-doc list by Corion
in thread Need to speed up many regex substitutions and somehow make them a here-doc list by xnous

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