use warnings;
use strict;

open my $fh, '<', 'in.txt'
  or die $!;

open my $wfh, '>', 'out.txt'
  or die $!;

binmode $fh, ":utf8";
binmode $wfh, ":utf8";
binmode STDOUT, ":utf8";

while (<$fh>){
    chomp;
    print $wfh "file: $_\n";
    print "stdout: $_\n";
}