how to install linux on external hard drive

Connect the external hard drive to your computer. What does mean hard as format: a small swat and rest space cut. In order to get your operating system onto an external hard drive, you first have to set up the hard drive mechanically, and then you can work on getting the operating system installed. So I have a toshiba external hard drive 320 giga byets, and I want to install linux ubuntu. Can I install an operating system on an external hard drive? There’s nothing special about installing to USB drives.