HOW TO: Make a Bootable USB by Downloading an .ISO or an Image Directly to Your Thumbdrive

When you want to install a new OS, you usually create a bootable USB flash drive with the .iso of that OS. To do that you can use GUI programs like Etcher or Rufus or the dd command. Or maybe you’ll take the more convinient route and create a multiple-ISO bootable drive.

But, maybe, you just want to create an Ubuntu LTS bootable flash drive and just throw it in your backpack or hang it on your keychain, just in case you’ll ever need it. Maybe, for any reason, you don’t want to download the iso or image to your HDD/SSD. Maybe you’re out of space. But you really need to make a bootable drive.

You can just write the ISO files directly to your USB drive as you download it from the internet.

NOTE: this works on UNIX and UNIX-like systems like Linux and macOS. It won’t work on Windows or, at least, I couldn’t get it to work. If you can get it to work, send an email and walk us through it…

1. Insert your USB thumbdrive into the USB port

2. MAKE SURE you know your thumbdrive’s disk ID.

    • On macOS – you can find your thumbdrive’s disk ID via Disk Utility app or from the terminal if you run diskutil list

    • On Linux – run lsblk from the command line.


3. Unmount the drive. This is important.

4. You will need wget. On linux it should already be installed on your machine. On macOS you can install it via Homebrew with brew install wget

5. Now, let’s flash the drive with an ISO. Open the terminal and:

    • on macOS run: sudo wget "" -O /dev/diskXsX ( replace diskXsX with your drive ID )

    • on Linux run: sudo wget "" -O /dev/sdX ( replace sdX with your drive ID )


6. Once the file has been saved on your thumbdrive,  just wait a second to make sure it’s done writing, plug the thumbdrive out ( it isn’t mounted so you can just plug it out ) and use it like you’d use any other bootable flash drive.