When creating OS installation media, a lot of people suggest using various third party tools, such as Etcher and others. However, it’s fairly easy just using dd (Data Dump) on any Unix-like OS to do the same thing.

Zero Out the Disk

Insert a USB stick and identify its appropriate name under /dev/. For MacOS, you can try diskutil list - just identify the disk that wasn’t there before you inserted your USB stick. Then use diskutil unmountDisk /dev/rdisk# where # is the disk number. Note the r in rdisk - stands for “raw”, in other words, the disk device itself, not a filesystem or partition on the device.

Now to zero out the disk, use dd with an input file (if=) of /dev/zero and an output file of /dev/rdisk#:

$ dd if=/dev/zero of=/dev/rdisk4 bs=1m

In this example we’re zeroing-out rdisk4 with a block size (bs=) of 1 megabyte.

On MacOS, you can use CTRL+T (not CMD, CTRL) to check progress. It’ll report the number of bytes written over a number of seconds.

Write the ISO to the disk

Once that finishes, you can use the same command, just with a different input file (if=) to write the ISO to disk:

$ dd if=/Users/jah/Downloads/some-os.iso of=/dev/rdisk4 bs=1m

When finished, ensure the disk isn’t mounted (eject it if so) and you’re good to go!