[PLUG] No space left on device

[John Jason Jordan]

I recently encountered this and it turns out that my / partition was,
indeed, full. At the last Clinic I added ~50GB of free space on the
drive to /, making now a total of 84GB. And now it is happening again.
Something in / has eaten the entire new space.

Note that ~/ is on the same drive, but a different partition. According
to Thunar the ~/ partition is only 64% used, 138GB of free space.
The device is a 480GB SSD. Palimpsest shows both partitions and no
unallocated space.

I used Thunar to check Properties on everything in / and found nothing
out of the ordinary. I need some command line tools to find the pig
that is using all my space. Also I need to find out what is causing the
pig to be so hungry. Suggestions?