isosize(8) -- Linux man page
NAMEisosize - outputs the length of a iso9660 file system
SYNOPSISisosize [-x] [-d <num>] <iso9660_image_file>...
This command outputs the length of an iso9660 file system that is contained in 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 (or errors) it will output the size of the iso9660 file system in bytes. This can now be a large number (> > 4 GB).
- output in humanly readable form the block count and the block size. Output uses the term "sectors" for "blocks".
- -d <num>
- only has affect when "-x" is not given. The number output (if no errors) is the iso9660 file size in bytes divided by <num>. So if <num> is the block size then the output number will be the block count.
The size of the file (or block device) holding a iso9660 file system can be marginally larger than the actual size of the iso9660 file system. One reason for this is that cd writers are allowed to add "run out" sectors at the end of a iso9660 image.