$text =~ s/(\d)(?=(\d\d\d)+(?!\d))/$1,/g;



$text =~ s/(\d)((\d\d\d)+\b)/$1,$2/g;



while ( $text =~ s/(\d)((\d\d\d)+\b)/$1,$2/g ) {
   # Nothing to do inside the body of the while -- we merely want to reapply the regex until it fails
}



undef $/;    # Enter "file-slurp" mode.
$text = <>; # Slurp up the first file given on the command line.




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Copyright 1997-2025 Jeffrey Friedl