This command outputs the length of an iso9660 file system that
is contained in the given file. That file may be a normal file or
a block device (e.g. /dev/hdd or /dev/sr0). In the absence of
any switches (and errors) it will output the size of the iso9660
filesystem in bytes. This can now be a large number (>> 4 GB).
Show the block count and block size in human-readable form.
The output uses the term "sectors" for "blocks".
-d, --divisor number
Only has an effect when
-x is not given. The value shown (if no errors)
is the iso9660 file size in bytes divided by
number. So if
number is the block size then the shown value will be the block count.
The size of the file (or block device) holding an iso9660
filesystem can be marginally larger than the actual size of the
iso9660 filesystem. One reason for this is that cd writers
are allowed to add "run out" sectors at the end of an iso9660