Howdy folks, this is just another somewhat plagiaristic post for my own future reference. I found this info hyah and unfortunately I was unable to retrace my steps to find my original source on where to locate the .dmg file in the installer package.
Download the latest version of Yosemite/El Capitan from the App Store and make sure you’ve formatted your USB thumb drive with the Disk Utility. Then open up a terminal and issue the following commands:
Yosemite
sudo /Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/YourThumbDriveHere --applicationpath /Applications/Install\ OS\ X\ Yosemite.app --nointeraction
El Capitan
sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/YourThumbDriveHere --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app --nointeraction
To locate the disk image or DMG file directly from the installer package:
- Open up Finder > Applications
- Right-click the Install OS X Yosemite/El Capitan package and select “Show Package Contents”
- Navigate to the Contents > SharedSupport folder
- Find the disk image “InstallESD.dmg”