See the DigiUSB→Echo example and the applications in the “Digispark - Example Programs” folder for an example of how to use the DigiUSB library.

On the computer side you can use the included command line tools in the DigiUSB Programs folder:

• If you're on windows make sure to install the DigiUSB driver in that folder (different from the main Digispark driver)

• digiusb - this program is like the Arduino serial monitor, allowing you to send and receive messages to/from a Digispark running DigiUSB
• send - this allows you to send data/text to a Digispark with DigiUSB - run with –help to see all options
• receive- this allows you to receive data/text from a Digispark with DigiUSB - run with –help to see all options

Also check out the ruby gem: http://rubygems.org/gems/digiusb

The rubygem is a package installable using the rubygem package manager (you wont get any benefit from just downloading the files from github, unless you also use the gem tools to compile it in to a gem and install it. (Copied from a forum post by Bluebie)