#!/usr/bin/perl
use strict;
use warnings;
use Encode qw(from_to);

my $from     = $ARGV[0];
my $to       = $ARGV[1];
my $in_file  = $ARGV[2];
my $out_file = $ARGV[3];

open my $input, "<", $in_file or die "$!";
open my $output, ">", $out_file or die "$!";

if($from eq 'UTF-16LE'){
    $/ = "\012\000";
}

while(my $octets = <$input>){
    from_to($octets,$from,$to);
    print $output $octets;
}

close($input);
close($output);