For sufficiently recent versions of shuf. It looks (... at a skim of the history, I could be confused) like older versions use pid, ppid, uid, gid, and time.

For sufficiently recent versions of shuf. It looks (... at a skim of the history, I could be confused) like older versions use pid, ppid, uid, gid, and time. In that case that's likely to be more practical than brute force if you've generated a password with notionally more than ~40 bits of entropy. That said, I suspect most people are indeed on a platform with a sufficiently recent version of shuf. (And a sufficiently old version may lack the random-source option.)