volname - return volume name
Volname returns the volume name for a device formatted with an ISO-9660
file system, typically a CD-ROM. It also works with normal files that contain
a ISO-9660 file system.
The file name can be specified on the command line. If omitted, it
defaults to /dev/cdrom.
Volname was written by Jeff Tranter (email@example.com) and is released
under the conditions of the GNU General Public License. See the file COPYING
and notes in the source code for details.