#!/usr/bin/env perl use strict; use warnings; open (my $original, '<', 'data.txt') or die $!; open (my $fh, '>', 'output.txt') or die $!; my $first = <$original>; print $fh $first; my @replace = $first =~ /"([^"]*)"/g; while (my $line = <$original>) { $line =~ s/(\d{2})/$replace[$1]/g; print $fh $line; } close $original; close $fh;