Mac OS X DMG disk images
Make sure you have the kernel modules to support HFS and loop mounting.
modprobe loop modprobe hfs modprobe hfsplus
Check if the DMG file is compressed or raw.
It will say something about HFS data or something about compressed data. If the dmg is compressed then 7zip handles these well. You can also use dmg2img, but 7zip is more general and flexible.
7z x example.dmg
The disk will be split into separate files based on partition. There may be lots of small partitions of little interest. Typically, the largest partition file will be the one of interest.
mkdir -p /media/dmg mount -t hfsplus -o loop example.dmg /media/dmg # Or try: mount -t hfs -o loop example.dmg /media/dmg