#!/usr/bin/perl
use strict;
use warnings;
open(IN, "<:encoding(UTF-8)", "in.txt") or die "Can't open input file: $!";
open(OUT, ">:encoding(UTF-8)", "out.txt") or die "Can't open output file: $!";
while (<IN>) {
s/([^\t]*)\t([^\t]*)\1([^\t]*)\t/\t$2$1$3\t/;
print OUT $_;
}
close IN;
close OUT;
print "Replacements done";
<STDIN>;