Backup Raspberry Pi SD card

Step 1 : find your SD card

In the terminal, run diskutil list and look for the SD device. Mine was /dev/disk2.

** Step 2: backup your card**

Run the following command:

sudo dd if=/dev/rdisk2 of=backup.img bs=1m

Where if is the input file, of the output file, and bs the block size. This will, however, create a backup the size of your SD card, even if it's not full. My 8GB card created an 8GB image even though only 2GB was used.

NOTE: I used /dev/rdisk2 instead of /dev/disk2 because it's about 8 times faster.