If I have a sparse file representing a block device, then how can I efficiently restore the file over a network? Ideally, I'd use rsync -S host:file /dev/sdb, but rsync won't write to block devices. ...
If I use rsync with the --size-only and --sparse options together, if a file already exists at the destination as a full file (otherwise the same) it's not overwritten. If I omit the --size-only ...