To create a bootable CD that you can use to manipulate Linux-formatted drive volumes, take the following steps.
- Download the latest version of gparted-live -- make sure to get the ISO disk image.
- Burn the ISO to a CD using Disk Utility. This CD will boot your Mac into an open source Linux OS. Nothing in OS X or on your hard drive is changed, and you don't need to use Boot Camp or any emulation software.
- To boot into the CD, select it in the Startup Disk System Preferences pane and then restart. Warning! Use a USB keyboard and mouse, as this Linux OS cannot handle Bluetooth wireless.
- Be somewhat amazed as your Mac reboots and Unix code streams down the page. There are a couple of prompts for input along the way, before you arrive in the GUI of the OS.
- The gparted (Gnome Partition Editor) software launches automatically, and you can select any mounted volume for information and manipulation, and many filesystems are supported. There is extensive online documentation and support for this software.
- Be very careful! Formatting deletes all your data, so obviously the usual precautions about backing up apply. Be sure to select the correct volume on which to make any changes!
- Shut down when you have finished. Warning! Your Mac may not respond to the alt (option) key when you restart and you may have to manually eject the CD before you can reboot into OS X.

