I suspect perl is DWIMing your potential $1_0_0_ into $1. The actual fix is to just encose the '1' in curlies like s/ ... /${1}0_0$2/. You use curlies to disambiguate interpolated variables where needed.

In reply to Re: search, replace and backrefrences by diotalevi
in thread search, replace and backrefrences by Helter

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