So I have dd running in one terminal, copying an image to an SD card, and occasionally run "kill -USR1 <pid>" (where <pid> is the dd process id) in another to prod dd into giving me some status info.

Every so often I go back to the second terminal, hit "up"+"enter" to re-run the command, and flick back to the first to check progress.

Except on one occasion I hit "up"/"enter" on the first terminal, where it had no effect as dd was already running, so I forgot about it. Of-course when dd finished the terminal then grabbed the up/enter from the keyboard buffer and started to re-image the SD card.

Given that I'm writing a duplicate image over the top of the SD card is it "safe" to kill the second dd or is there a risk that the SD card will end up corrupt?

It's only a 4GB card so I'm not expecting an answer before it's too late to matter, this is more idle curiosity. Unless it turns out I hit up+enter more times than I thought....

Mark