How do I get df to work on jump drive?

[Knute Johnson]

Thorny wrote:
> On Fri, 20 Mar 2009 20:44:06 -0700, Knute Johnson posted:
> 
>> Matthew Flaschen wrote:
>>> Knute Johnson wrote:
>>>> I've got a jump drive that I use for nightly backup.  I can't seem to
>>>> get an accurate space left or used.  The disk is /dev/sdb1 and the
>>>> mount is /media/usbdisk.
>>> Well, it needs to be mounted when you run the command.
>>>
>>> Matt
>>>
>>>
>> I know that and it is.
> 
> I think Matthew's point was that it doesn't appear to be from the output
> you showed us, even though you told us it was. Are you sure it's mounted,
> can you navigate to it and read files? What is the output of the command,
> mount?

But I was wrong.  It was mounted at one point but not any more.  Is 
there a simple way to confirm that a jump drive is mounted?

Thanks,

-- 

Knute Johnson

"The urge to save humanity is almost always a false front for the urge 
to rule."

   H.L. Mencken