Great writeup from Lifehacker.com on creating a USB Flash Drive Installer for OS X Yosemite (10.10) using Terminal.
- Download the Yosemite installer, if you haven't already.
- Insert an 8GB (or larger) flash drive, and give it a name. For this tutorial, we've named it Untitled. Make sure the drive is formatted OS X Extended (Journaled). If it isn't, hop into Disk Utility and format it so it is. If you have any important data on the drive, back it up now, since this process will completely erase it.
- Open up the Terminal, either through spotlight or by double-clicking on it in /Applications/Utilities.
- Type (or copy and paste) the following command into your Terminal window (replacing Untitled with the name of your drive) and press Enter:
- sudo /Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ Yosemite.app --nointeraction
- Type in your password when prompted and press Enter.
Let the command work its magic. Don't interrupt it until you see the final line that says "Done" before it returns you to the prompt. This could take as long as a half hour, so be patient!