Type dmg2img into the command line followed by the name of the DMG file you want to decompress.

Opening A .Dmg File How To Do It

But if you really want to do this on Linux, without having to rely on Mac, heres how to do it.

DMG is Apples proprietary disk image format, native to Mac OS X.

There are actually a whole bunch of different types, format and options within this format.

There are options for encryption, compression, and different kinds of partition schemes, among others.

Unfortunately, this can make things pretty confusing when were trying to gain access to the data contained in one of these images.

Although the.dmg file extension is usually used, they can also sometimes have an.img extension, or in some cases no extension at all.

You may also sometimes find FAT and ExFAT files systems, as well as variations on HFS.

Opening A .Dmg File Plus Kernel Modules

Linux supports HFS through the hfs and hfsplus kernel modules.

Plug in a USB drive formatted with the Mac OS Extended file system.

If your particular distribution doesnt have the appropriate modules, you will likely get an error message.

On Ubuntu, youll get a popup window declaring Ubuntu: Unable to mount.

This is especially the case for certain distributions that are a few years old.

While its nice to have the option to mount the images were working with, this is really the only functionality were losing without having the hfs and hfsplus modules.

The two programs were going to use later on (P7ZIP and dmg2img) do not require kernel support to function.

The following partition schemes have all been tested with the techniques discussed here.

DMG images with partition scheme types of CDDVD and GUID Partition Map do not appear to work with the techniques described here.

The mnt at the end of the command specifies where were mounting the image.

Unsupported images include sparse images, sparse disk bundles, CDDVD masters, and images with partition schemes of the CDDVD or GUID Partition Map types.

To get around this little obstacle, well use dmg2img (see below).

Youve done file compressedimage.dmg and you got compressedimage.dmg: bzip2 compressed data.

The fix Thats easy: use dmg2img to convert it to an uncompressed image.