`dd` can be coerced into producing a progress report (by signalling it with `SIGUSR1`) and can be told to start writing part way through (using `seek`)
You then just need a source of random bytes, such as /dev/urandom
`dd` can be coerced into producing a progress report (by signalling it with `SIGUSR1`) and can be told to start writing part way through (using `seek`)
You then just need a source of random bytes, such as /dev/urandom