What quantumgravity is trying to explain is that pseudo-randomness really is
a problem if you use it a lot. Like every millisecond. Patterns then appear.
It is not random anymore. When you run it once, it usually is good enough
because the attacker cannot know the state of the system when you called the
pseudo-random generator. That state is used to seed the pseudo-randomness.
But you are right, you had better use real randomness (well, not
"quantum-mechanics real" but "dice real") for a long-lived password. In
theory, the command I gave above is easily modified to use real randomness:
$ cut -d / -f 1 /usr/share/hunspell/en_US.dic | shuf
--random-source=/dev/random | head -6 | tr '\n' ' '
However, I fired this command eight minutes ago and it has not output
anything yet! That must be because environmental noise (that the kernel uses
to feed an entropy pool and then generate randomness, which is accessible
from /dev/random) is scarce.
