Create bootable usb with `dd` command

ryer:~$ diskutil list
/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            SSS_X64FREE_EN-US_DV9  *33.2 GB    disk2

ryer:~$ diskutil unmountDisk /dev/disk2

ryer:~$ sudo dd bs=1m if=IMAGE.ISO of=/dev/rdisk2  # C-t to view progress