On 22/11/16 16:45, Billy Crook wrote: > Pardon my html email, but the inline attached images are relevant. > > I am trying to use dd to zero the (first and) last 512MB of a range of > partitions on a range of disks. The blocksizes vary, and I put together a > one-liner which I thought should do the trick, but it doesn't. > > i specify a bs to match the partition's block size as reported by blockdev > --getbsz. I specify a seek= that is less than the number of blocks that > blockdev --getsz reports. I should think this would begin writing before > the end of the partition and continue until the end. But instead, I > receive "cannot seek: invalid argument" (0b copied) > > What am I doing wrong?
It's best to just copy & paste text, rather than sending large screenshots. It's probably best to use `blockdev --getsize64` to get the size in bytes and divide that by whatever you're specifying to the `dd bs=` parameter. That will avoid any mismatch between block sizes. Also I notice negative values passed in some of the commands, which may be related to this mismatch.
