If this is a one-time scratch task, and it will finish in mortal time, and not an every-five-minute cron task, then who cares? If the system is in heavy load production, sprinkle sleep() calls in the main loop. Once it's done, you can move on with your life.

If it's a common task, or it exceeds rational usage limits, then it's time to see what tools may be better than the existing command-line resources.

Do a super-search on this site for the phrase "premature optimization" and you might get some related wisdom.

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