chgrp not permitted?

[Craig White]

On Thu, 2008-09-11 at 17:03 -0700, Robert Holtzman wrote:
> Running "sudo chgrp <name> mail" on a directory on a usb stick gives
> 
> "chgrp: changing group of `mail': Operation not permitted"
> 
> This is true for any file or directory on the stick, and yes, I entered 
> the password. I can't figure out how to copy to the stick without the 
> group being changed to root or how to change it after the fact.
> cp -p test1 /media/disk doesn't do it and
> 
> cp -preserve=mode,ownership,group,timestamp test1 /media/disk gives
> 
> "cp: invalid option -- e"
> 
> I have to be doing something wrong but I'm not sure what. Google and 
> Ubuntu forums were no help but I may be searching on the wrong terms.
> 
> Any help appreciated. Thanks.
----
a lot of details are missing but presuming that this USB disk is vfat
filesystem, then there would nothing like POSIX users/groups and all
files/folders are owned by the user mounting the filesystem and cannot
be changed because a vfat system wouldn't support it.

If what you are trying to do is to copy files from one system to another
and preserve those things (owner/group/timestamps), tar the file, copy
the tar file onto the USB 'stick', copy the tar file onto your next
Linux host and untar it there and the those attributes should be
preserved.

If my assumption about vfat filesystem is not correct, more details
would probably help drive a solution.

Craig