I have two devices /dev/sdc1 and /dev/sdc3./dev/sdc1 is mounted on / and /dev/sdc3 is mounted on /home.The problem is that the device sdc1 is full whereas sdc3 has a lot of spare space. I want to determine where all that space on sdc1 gone (I suspect installed packages. a lot of them).I tried to use du (and ncdu which makes this info more visual) but it calculates size of the whole tree (/home is nested on /) and I want to know only what's filling one of my devices. Is there a way to do that?To clarify: I need some way to calculate usage of a device, not just exclude some subdirectories (which may be applicable in my situation, but I believe it can be more complex than that)
Estimate file space usage on a device (not in a directory)
disk usage
To limit to a single device you need the -x parameter of du-x, --one-file-system          skip directories on different file systemsA useful graphic front-end to du is xdiskusage.