I've done something similar for ID numbers. It is indeed a little shorter:

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;
 }
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I didn't use the dotdot in the list constructor, as you see. I think you could have written 'a'..'z' (that is, use the quotes) and not get the bareword warning. However, note that I leave out 'l' because it looks too much like a '1', and it should be somewhat human readable/reproducable, right?

—John