Show processes that block umount

A quick oneliner to list running processes that prevent a filesystem from being unmounted. Using lsof for this.

Another quick one: I forget this command on a permanent basis, so I write this down here — maybe this helps.

lsof +f -- /media/mountpoint

Update on 2021-11-21

You could also use fuser. I prefer this one because somehow I cannot use autocompletion with lsof and fuser lets me complete the paths.

fuser -vm /media/mountpoint