Ubuntu team developed live file-system which can be booted on system without installing the operating system on hard disk (even with persistent storage which allow you to save changes on pen drive). Most of the Linux systems incorporated this technology in their distributions which allowed people to run Linux distros on CD/DVD or pen/flash drive prior installing it on their systems. By live-booting, you can check that your system is supported by the Linux distribution and take a test drive of the operating system. BUT, how you’re going to run your favorite Linux from pen drive? So, I’m going to tell you the procedure to Boot and Run Linux from pen drive using UNetbootin.