[yoursunny]

In case the second sudo wants to ask for password but there's no disk space for logging, it's safer to:

sudo bash -c 'dd if=/dev/zero of=/zeros; rm -f /zeros'

[willis936]

I typically don't put sudos in my scripts but have found filling all free space is particularly hazardous. I ran into rm permissions issues once and had to sneak my way into a recovery environment to remove the file. I haven't ran into sudo timing out during the zeroing, but it is a hazard. This is a good tip.