Testing Environment Variable List Here's the contents of my /etc/environment file, setting the various testing environment variables for the full test platform. For LCD, the last two digits (4, 20) are for four row, 20 column units. If you only have a two row by 16 column unit, leave those last two digits off. PI_BOARD=1 RPI_ARDUINO=1 RPI_ADC=1 RPI_MCP3008=1 RPI_MCP4922=1 RPI_SHIFTREG=1 RPI_LCD=1 RPI_SERIAL=1 RPI_HCSR04=1 BB_RPI_LCD=5,6,4,17,27,22,4,20 RPI_RTC=1 RPI_MCP23017=1 RELEASE_TESTING=1