How can I open a .dmg file?

Question

I've got a .dmg file, and I can't figure out how to open it. How can I open it?

Solution 1

Install dmg2img.

Next, read the package information page and the manual page to see if it is useful to you.

The application seems to convert .dmg to a file that can be mounted using the mount command:

dmg2img file.dmg imagefile.img

From your Wikipedia article, the next command seems to be available to do that:

sudo mount -o loop -t hfsplus imagefile.img /mnt

In this way, the file imagefile.img is a result from dmg2iso and the contents will be available at /mnt. If the hfsplus type is not detected, you might need to load the kernel module for it:

sudo modprobe hfsplus

When done, you can unmount it by running:

sudo umount /mnt

Solution 2

To extract it, it is much easier to use 7zip:

7z x file.dmg

Solution 3

This works for me:

• Extract using 7z x
• Locate the hfs partition file
• Mount it to a directory

Extract using 7z x

root # aptitude install p7zip-full
root # 7z x ../mysql-5.5.28-osx10.6-x86_64.dmg 

7-Zip [64] 9.20  Copyright (c) 1999-2010 Igor Pavlov  2010-11-18
p7zip Version 9.20 (locale=en_IN,Utf16=on,HugeFiles=on,4 CPUs)

Processing archive: ../mysql-5.5.28-osx10.6-x86_64.dmg

Extracting  0.MBR
Extracting  1.Primary GPT Header
Extracting  2.Primary GPT Table
Extracting  3.free
Extracting  4.hfs
Extracting  5.free
Extracting  6.Backup GPT Table
Extracting  7.Backup GPT Header

Everything is Ok

Files: 8
Size:       125475840
Compressed: 117543935
root # ls
0.MBR  1.Primary GPT Header  2.Primary GPT Table  3.free  4.hfs  5.free  6.Backup GPT Table  7.Backup GPT Header

Locate the hfs partition ( here it is 4.hfs file ):

root # ls -l
total 122548
-rw-r--r-- 1 root root       512 Feb  5 16:06 0.MBR
-rw-r--r-- 1 root root       512 Feb  5 16:06 1.Primary GPT Header
-rw-r--r-- 1 root root     16384 Feb  5 16:06 2.Primary GPT Table
-rw-r--r-- 1 root root      3072 Feb  5 16:06 3.free
-rw-r--r-- 1 root root 125435904 Feb  5 16:06 4.hfs
-rw-r--r-- 1 root root      2560 Feb  5 16:06 5.free
-rw-r--r-- 1 root root     16384 Feb  5 16:06 6.Backup GPT Table
-rw-r--r-- 1 root root       512 Feb  5 16:06 7.Backup GPT Header

Mount it to folder:

root # mkdir t
root # mount -oloop 4.hfs t
root # cd t/
root # ls
mysql-5.5.28-osx10.6-x86_64.pkg  MySQL.prefPane  MySQLStartupItem.pkg  ReadMe.txt

Solution 4

If you succeed with the instructions from Lekensteyn and binfalse more power to you. If you are getting

$ lsmod | grep hfs
hfs                    54782  0 
hfsplus                84912  0
$ sudo mount -o loop,ro -t hfsplus imagefile.img /mnt
mount: wrong fs type, bad option, bad superblock on /dev/loop0,

Right now Ubuntu only comes with dmg2img version 1.6.2 and version 1.6.4 sometimes makes a difference. Also you can extract specific partitions from a dmg and only some of them are hfs+

$ dmg2img -l file.dmg
partition 0: Protective Master Boot Record (MBR : 0)
partition 1: GPT Header (Primary GPT Header : 1)
partition 2: GPT Partition Data (Primary GPT Table : 2)
partition 3:  (Apple_Free : 3)
partition 4: disk image (Apple_HFS : 4)
partition 5:  (Apple_Free : 5)
partition 6: GPT Partition Data (Backup GPT Table : 6)
partition 7: GPT Header (Backup GPT Header : 7)
$ dmg2img -p 4 file.dmg imagefile.img

• Current Ubuntu versions come with 1.6.5 as of version 14.04

Solution 5

When using dmg2img file.dmg imagefile.img on linux if you get ERROR: Inflation failed message, just install 7zip as

sudo aptitude install p7zip-full

and issue the following command on terminal

7z x your_file.dmg

• find the InstallMacOSX.pkg/InstallESD.dmg
• issue the command dmg2img InstallESD.dmg imagefile.img on the terminal.

Now you can mount imagefile.img with

modprobe hfsplus

and then

mount -t hfsplus -o loop mountain.img /mnt

View more solutions

Comments

[HDave]

This will not work if the dmg file has 10.6+ compressed files in it.

[tuxdna]

I get this error - mount: wrong fs type, bad option, bad superblock on /dev/loop0

[Lekensteyn]

@tuxdna Do you really have a HFS image? Check the output of file file.dmg. You can also try 7z l file.dmg to list the contents.

[tuxdna]

I am using dmg2img v1.6.2. I ran dmg2img on mysql-5.5.28-osx10.6-x86_64.dmg which created mysql-5.5.28-osx10.6-x86_64.img, but it doesn't mount.

[tuxdna]

@Lekensteyn Thanks! Now it works. Check my answer below.

[Lekensteyn]

You can specify the single file you want to extract: 7z x ../mysql-5.5.28-osx10.6-x86_64.dmg 4.hfs

[rinni]

Thanks, 7z did the job, whereas dmg2img complained about a corrupted dmg image.

[vog]

Note that 7z works only for unencrypted dmg images

[Aaron Franke]

This just created a file called 0.unknown partition for me.

[Olorin]

Multiple answers suggest directly using 7z on the dmg file. Why convert it then?

[cat]

@Olorin this is for when 7z x your.dmg fails with Can't open as archive: 1, and when dmg2img's output won't be accepted by mount either. I'll clarify

[Skylar Ittner]

I'm getting segmentation faults when trying to use a multipart DMG.

[Lekensteyn]

For future readers, @SkylarIttner reported the issue here: github.com/Lekensteyn/dmg2img/issues/7

[Samir Patel]

This utility does not support password protected .dmg files

[kamae]

I was facing same problem but this answer helped my situation.