Just wrote this thing. Putting it here, in case anyone needs it.
perl -e 'my @c = (('a'..'z'), ('A'..'Z'), (0..9)); for(1..128) {print $c[int(rand($#c+1))]}'
It creates random passwords, with the length specified by the number following “1..”, which is 128, in this example.
Example outputs:
lFcQYCtPl653r9D3cSfcFyeLJlbdDNPrxeIjkf6c77CjBRgtTRHKKL824La4giNLJkza66CzlecoOExPeuEJyQAnHFOQpcPsPbRiycSttCXwGhYK40BfQFlLWJapPltu HQVfvdUrkOOExPAiH5ry7u177TjgsDnfW4FlVuDeU3f833kPAe9z4XKZuKhqYaTZAd7wzuAgX8eTWM79TgDymNJWZ8RNRa30DuNSd5xCZ6rkMS00q35R4jWxR7Ztzbfn dCAlGY0KfNlPfp9D2DuhNHM8oqXFijXrjaRWxidzydzjUF61i0sAitCiZUiOrBsZwToqWXXMbxxjo6kKOIb5MxFQPkuIfsteavxd6gX2I7sQhJh4MmztondoikQ4Pb6i