Question: how to install a dmg file on linux?
Answer:  Install hfsprogs which enables operation with HFS and HFS+ on Linux via ports of mkfs and fsck. sudo apt-get install hfsprogs.
 Mount or remount the HFS+ drive. sudo mount -t hfsplus -o force,rw /dev/sdXY /media/mntpoint. or. ... 
 If the drive is partially corrupted or was unmounted with an error run: