sudo tail -c 1024 /dev/sda2 | hd the entire /dev/sda2 device rather than seeking to the end. This takes a very long time with large disks. Deltik gives a nice explanation here - https://superuser.com/questions/1267402/how-do-i-tail-a-block-device-in-linux - of how ioctl can be used to obtain the size of a block device instead of fstat.
