I have a bootable USB for OSX El Capitan that I got from a friend. I need to make a copy of that on my USB. How do I clone that or make it into an ISO and clone the ISO into my USB in Mac?
You should be able to use Disk Utility included with your Mac. Connect both USB drives to your Mac. Then do the following.
- Click on the Restore tab
- Drag the source USB drive over to where it says Source
- Drag the destination USB drive over to where it says Destination
- Click the Restore button
You can use the standard UNIX utility dd
plug in the flash drive you want to clone
open terminal (Apple Key + space or Apple Key + f, whichever brings up the search box [I forgot] and type terminal, then hit enter)
dmesg | tail -n 10
that's a pipe not an L (usually on the backslash key)
hit enter. check what drive showed up. I'll use sd2 for my example (could be ada1, or sda1, etc)
sudo dd if=/dev/sd2 of=usb.img bs=4096
then unplug the flash drive when it's finished. plug in the blank one.
sudo dd if=usb.img of=/dev/sd2 bs=4096
to image the blank USB flash drive. It's good practice to verify that the second USB drive was assigned the same device name. Likely it was.