This post is from Langui’s post at: https://langui.sh/2011/04/02/using-dd-in-os-x/
Doing device level copies with dd is a reasonably common Linux task, but not something OS X users typically do. However, if you find yourself needing to write an image file1 to a microSD card or some other media then here’s a simple guide to using it.
First, you’ll want to see the device labels.
diskutil list /dev/disk0 #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *250.1 GB disk0 1: EFI 209.7 MB disk0s1 2: Apple_HFS Macintosh HD 249.7 GB disk0s2 /dev/disk2 #: TYPE NAME SIZE IDENTIFIER 0: FDisk_partition_scheme *2.0 GB disk2 1: DOS_FAT_32 THUMB_DRIVE 2.0 GB disk2s1
The output from above shows that we have a mounted 2GB USB flash drive named “THUMB_DRIVE” that has been given the identifier /dev/disk2. To write to it we need to unmount it, but ejecting it in the normal Mac way won’t work here.
diskutil unmountDisk /dev/disk2
There we go! Now we just need to write our image file.
dd if=inputfile.img of=/dev/disk2
The shell will appear to hang, but you can check disk activity to see that it’s writing. Once the command returns you’re done!