On Mac, it is easy to create a CD image using Disk Utility. On recent versions of Mac OS, however, it is disabled to create images of audio CDs—the function is grayed out in the menu when you insert an audio CD. In order still to create an image from an audio CD, there are a couple of ways on the command line.
hdiutil is the command line version of Disk Utility. Run the following command to create the CD image:
hdiutil create -srcdevice /dev/diskn -format UDTO image.iso
Replace n with the correct disk number, which can be found using diskutil:
dd is a low-level file copy utility which is oblivious of the type or the content of file. As in Unix-based OS every device is a file, you can copy a “file” corresponding to a drive to a normal file:
dd if=/dev/diskn of=image.iso
You will need to unmount the drive before copying it:
sudo umount /dev/diskn
When creating an exact copy of a (data) CD/DVD using Disk Util, select the “device” instead of the “folder” within the device. And use DVD/CD-R master as the format.
By default, Mac assigns the file extension of .cdr, which is exchangeable with .iso.
If you want to create a cross-platform data CD image using hdiutil:
hdiutil makehybrid -iso -joliet -o image.iso /input/path
man pages, e.g., man hdiutil or https://developer.apple.com/library/mac/#documentation/Darwin/Reference/ManPages/man1/hdiutil.1.html