How to check what process is writing to hard drive in shell

Question

Currently the free space of my hard disk is shrinking for unknown reason. The free space keeps reducing until no space lefts. I don't know what's the cause, so I want to inspect to see what process is the culprit and terminate it.

Answer 1

iotop is to the hard disk what as top is to the CPU.

Among other things, it displays how many bytes per second all available proccesses are writing to the disk.

On Ubuntu, you can install it with apt-get install iotop.

Answer 2

lsof +d / | awk '$4 ~ /.*[uw]/' will list all processes with files open for reading or updating.