Ask Different is a question and answer site for power users of Apple hardware and software. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

How can I clone a CD or DVD to an ISO or DMG, using just the CLI, so that I can attach it to a VirtualBox VM.

I often clone CDs or DVDs using the following commands:

diskname=`df -kh /Volumes/* | grep -o Volumes.* | cut -d"/" -f2`
diskname=`echo $diskname | sed s/\ //g` # remove spaces
device=`df -kh /Volumes/* | grep Volumes | cut -d" " -f1`

sudo umount $device
dd if=$device of=~/Desktop/$diskname.iso bs=2048
hdiutil eject $device

The result is a .ISO on my desktop that is, as far as I can tell, a bit clone of the CD or DVD.

However, when I boot a VirtualBox Windows XP VM and attach the ISO, Windows says it cannot read it.

share|improve this question
up vote 3 down vote accepted

You can use hdiutil to create the disk image, then convert to a hybrid format:

hdiutil create -srcdevice $device $diskname
hdiutil makehybrid -o $diskname.iso -joliet -iso $diskname.dmg

NOTE: this method does not require unmounting the device first.

share|improve this answer
That was it. I forgot Windows needs joliet. Thanks. – user588 Mar 1 '11 at 9:07

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.