The search results that I've turned up have either been about determining whether a filesystem is mounted at a particular path or whether a particular path is being used as a mount point. I am looking for a way to determine whther or not a given device or file (i.e., a filesystem image) is mounted *at all*. This solution should be able to handle spaces in the path to device/file.

These, which I have seen in my search results, are NOT solutions:

* `mountpoint -q "${PATH}"` only tests if `${PATH}` is a mount point.
* Applying `grep -q "${PATH}"` to some output may not work because `${PATH}` may have spaces in it and the output of commands like `mount` has spaces in it.

Additionally, it should return WHERE a file/device is mounted to.