Given that these hashes are not salted, running a 'uniq' on the list of all users' password hashes would probably already cut it by half, if not more. Then you eliminate all the easy ones from wordlists, and post the remains on the internet for people with excess computing power to bruteforce.
I assume the first line you meant to pipe it through uniq afer the sort? Otherwise the only thing you've demonstrated is that sorting a file doesn't change its line count. :)
