WiringPi a GPIO Interface library for the Raspberry Pi
From Gordons website:
The Gertboard is a buffered IO interface board for the Raspberry Pi. It features 12 LEDs, 3 buttons, a high power motor driver, 6 open-collector medium power outputs, analog to digital and digital to analog converters and an ATmega 328p processor.
These pages serve as a demonstration of using the Gertboard with the wiringPi library from the command-line, in BASH and C. There are several pages in this series and I hope they might act as a tutorial and possibly even an aid to making sure your Gertboard is fully functional.