use strict;
use warnings;

my $in = '/x.txt';
my $out = '/y.txt';

open 0, "< $in" or
   die "Can't open $in for reading";
if (!open 1, "> $out") { close 0;
   die "Can't open $out for writing"; }

$a = <0>;

close 1 or die "Can't close output file $out";
close 0 or die "Can't close input file $in";
print $a;
exit;