I want to look at a raw block device (as in
/dev/sda) and know how much space is being used on the drive.
I don't know what type of file system is on the harddrive, nor do I have any way of figuring this out. A harddrive can obviously not be "empty", but what I do know is "empty space" is represented as bunch of zeroes (as in, output from
/dev/zero, not the ASCII character
How do I scan a block device, and then get an output telling me how many of the blocks are only filled with zero values?