If you must, this seems to work. 

 $x =~ s[(.{0,3}|)]["'$1" . (' ' x (3-length($1))) ."'\n"]ge;

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In reply to Re: How to split_and_pad string to n-th chars pieces with one regular expression? by BrowserUk
in thread How to split_and_pad string to n-th chars pieces with one regular expression? by bdimych

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