my $length= 6;  #how many digits to generate
my @letters= split (//, '0123456789abcdefghijkmnopqrstuvwxyz');

sub create_new_ID
 {
 my $result;
 foreach my $iteration (1..$length) {
    $result .= $letters[int(rand(scalar @letters))];
    }
 return $result;
 }