dd if=/dev/sda of=/dev/sdb bs=512

sda is the disk 1 you want to clone to sdb which is your disk 2
To see the progress bar status - include the flag “status=progress” (without the quotes) to see the cloning progress as it copies from one drive to the other.
i.e
dd if=/dev/sda of=/dev/sdb bs=512 status=progress