How to extract content of DMG without mounting it? I want add autoupdate system to my application. It downloads DMG from website, then extract new version of application from it.
Answer
Some .dmg files can be extracted by using 7-zip.
$ 7z x your.dmg
$ ls
your.dmg
0.MBR
1.Primary GPT Header
2.Primary GPT Table
3.free
4.hfs
5.free
6.Backup GPT Table
7.Backup GPT Header
...and after extracted the 4.hfs file:
$ 7z x 4.hfs
...you'll get the content of the .dmg file.
You could also mount the .dmg in Mac OS X using hdiutil command (which is also used by Homebrew Cask).
Please refer to this Ask Ubuntu question for more use cases on Linux.