the Linux-Kernel manages the GPIO-system under the path /sys/class/gpio. Use the following commands to manage the pins (e.g. GPIO 17):
activate GPIO 17:
echo 17 > /sys/class/gpio/export
deactivate GPIO 17:
echo 17 > /sys/class/gpio/unexport
configure GPIO 17 as input:
echo in > /sys/class/gpio/gpio17/direction
read the state from GPIO 17:
cat /sys/class/gpio/gpio17/value
configure GPIO 17 as ouput:
echo out > /sys/class/gpio/gpio17/direction
set GPIO 17 to low state:
echo 0 > /sys/class/gpio/gpio17/value
set GPIO 17 to high state:
echo 1 > /sys/class/gpio/gpio17/value