How to write from a linux boot cd to a usb with a mac

Question

I bought a book about C and it comes with a livecd of a custom distro with scripts pre-loaded. My quandary is that my current macbook pro was not equipped with a disk drive. I have temporary access to a Mac with a drive. How can I write the file from the cd to the usb so I can boot my mac? Can I write it directly from the disk, or do I need to convert it to an iso first? I am comfortable using the terminal, and do already know how to write an iso to a usb using dd if=and of=. The usb is also already properly formatted.