Where's my space?

I deleted some files to regain some space but I'm not seeing it! (*nix)

My file system says it's 99% full; it's a 4GB partition, and only 1.7GB is used; what gives?

There's likely a process holding onto the space that has yet to complete and terminate.

Run:   lsof | grep <your fs name> | grep deleted

This should reveal the process holding onto the space.  Trace the pid and do what is needed to end it.  This should free up the space reported by the file system.