How do I get df to work on jump drive?

[Thorny]

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?