Writing image to SD card

These are the steps to write an raspberry pi OS image to an SD card on MacOS 
 1. Insert card on reader 
 Identify the disk number 
 diskutil list 
 2. Unmount the disk 
 unmountDisk /dev/disk2 
 3. Write the image 
 sudo dd bs=1m if=hassos_rpi3-2.12.img of=/dev/rdisk2 conv=sync 
 4. Eject card 
 sudo diskutil eject /dev/rdisk2 
 Done! 
   
 https://www.raspberrypi.org/documentation/installation/installing-images/mac.md