Posted by (author unknown) at MacOSXHints.com
If you’ve tried burning the Mountain Lion installer to a standard DVD, you’ve probably noticed that it does not quite fit. Fortunately, there is a way around this.
The problem is that the size of the InstallESD image is fixed at 4.75 GB; slightly larger then a 4.7 GB single-layer DVD. However, the actual contents of the image occupy only 4.38 GB on disk, which will fit on a standard DVD.
In order to cram Mountain Lion onto a standard DVD, we need create a slightly smaller image file of the exact same format, copy the contents over, then burn it to a DVD.
I’ve written a small script to make this process quick and easy. Simply paste the code below into a plain text document and save it with a file extension of “.sh” To run the script, fire up Terminal and enter “bash /path/to/script.sh”. When this script finishes, you will have a new, smaller DVD image in your home folder, ready for burning.
NOTE: This script assumes you have the “Install OS X …