open my $handle, '<', $path_to_file or die "Not able to open file: $!";
chomp(my @lines = <$handle>);
close $handle or warn "Not able to close file: $!";

##</code><code>##

open my $fh, '>', "output.txt" or die "Cannot open output.txt: $!";

foreach (@lines) {
    print $fh "$_\n";
}
close $fh or warn "Not able to close output.txt: $!";

##</code><code>##

print $fh join ("\n", @lines);