ps ax | grep dd to find PID of dd (e.g. 5068) (now referred to as Y)sudo kill -USR1 Y
Alternatively, if you only have one instance of dd running (if you're not sure, this is probably the case), you can simply enter into the terminal sudo killall -USR1 dd without checking your PID.
Tip: You can have it automatically display progress by executing watch -n 10 kill -USR1 Y
Simple way:
Complicated way:
ps ax | grep dd to find PID of dd (it's the number on the far left, i.e.5068) (now referred to as Y)sudo kill -INFO Y
Alternatively, if you only have one instance of dd running (if you're not sure, this is probably the case), you can simply enter into the terminal sudo killall -INFO dd without checking your PID.