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 rubygem

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.

To install the rubygem, make sure you have libusb 1.x and ruby 1.9.x or ruby 2.0 installed (mac's and many versions of linux come with 1.8 installed, which is no good for this), then open a terminal and run 'gem install digiusb'. You might need to sudo that depending on your platform. Finally, you aught to be able to just type 'digiterm' in your terminal window and it will find the most recently attached digispark, connect to it, and start outputting everything printed via DigiUSB on the device and forwarding keystrokes from the terminal window in to the digispark.

You can get RubyGem from: http://rubygems.org/gems/digiusb