use warnings;
use strict;
sub output;

my $data = [ 1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 2, 2, 3, 34, 5, 6, 7, 8, 81 ];

output($data);

sub output {
    open my $fh, '>>', "output.txt" or die $!;
    print $fh $_, $/ for @{ shift(@_) };
}