SD card backup and restore - cjus/hydra-cluster GitHub Wiki
After configuring your Pis you're going to want to backup the modified SD's!
Here are instructions for Mac users:
Backup disk image
Find out where the SD card is mounted:
$ diskutil list
Back from mount point to disk image:
$ sudo dd if=/dev/disk2 of=./backup-image.dmg
Flash a disk image
Find out where the SD card is mounted:
$ diskutil list
Unmount the disk:
$ diskutil unmountDisk /dev/disk2
Write the backup onto the disk:
$ sudo dd bs=1m if=2016-09-23-raspbian-jessie-lite.img of=/dev/disk2
Checking progress
The above operations can take a while to complete. You can press Ctrl-T
to send a SIGINFO signal which will cause DD to display it's current status.