PKG, which may install things in any location.pkg's normally leave reciepts (usually in /Library/Receipts), though OS X offers no easy way to manage those recipts. This is somewhat complicated, because inside the DMG there may be a simple drag-n-drop solution, or a. A huge advantage of using a package manager is that it'll keep track of installed software and give you the ability to upgrade or uninstall it. Both of those package managers set up a self-contained directory ( /opt and /sw, respectively) with all the support files and executable code for software they install (and most packages respect it), and add themselves to your $PATH. Responsible developers will install to standard directories ( /Applications, /Library and ~/Library, /usr, etc.)įor command line software that you'd typically install from source, I'd recommend a package manager like MacPorts (my preference) or Fink over using an installer package. In this case, too, the developer is responsible for uninstall and responsivle for updates. Running it could install files anywhere on your system and run pre- and post-install scripts, and there's no built-in uninstall or upgrade mechanism (the system does keep a log of installed packages, though, so if you later run an installer package for a newer version of the software, it may behave differently than if it had been a first install).

Many developers are using the Sparkle framework to find and install updates. The application is responsible for doing any setup on first launch and responsible for providing an uninstall mechanism if anything is installed later on. When the disk image contains just an application (usually there will be some explanatory text asking you to drag it to your Applications folder), then all the code and support files are contained within that one file. dmg is just a virtual disk ('disk image'), and on its own has nothing to do with installation.

Dmg vs pkg