Since people might confuse 'l' and '1' (did you ;-) ?), O and 0, when jotting passwords down, i use the following char set for string::random :

use String::Random;
my $pattern = new String::Random;
my $size = 8;
# don't use i,I,1,l,L,0,O, etc..
$pattern->{'A'} = [ 'A'..'H', 'J', 'K', 'M', 'N', 'P'..'Z', 'a'..'h', 
+'j', 'k', 'm', 'n', 'p'..'z', '2'..'9' ];
print $pattern->randpattern('A' x $size);
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