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 de‐ faults to /dev/cdrom.
Volname was written by Jeff Tranter (firstname.lastname@example.org) and is released under the conditions of the GNU General Public License. See the file COPYING and notes in the source code for details.