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To control on the GPIO pins:

The external GPIOs are available under the /sys/class/gpio folder in Linux.

To control on the GPIO pins you need to calculate the GPIO number XX (*) and run the commands below:

# Export GPIO XX
echo XX > /sys/class/gpio/export

# Set GPIO pin Direction
echo "out" > /sys/class/gpio/gpioXX/direction
or
echo "in" > /sys/class/gpio/gpioXX/direction

# Set the value of an output pin
echo 1 > /sys/class/gpio/gpioXX/value
or
echo 0 > /sys/class/gpio/gpioXX/value

# Get the value of an input pin
cat > /sys/class/gpio/gpioXX/value

# Unexport GPIO XX
echo XX > /sys/class/gpio/unexport

You can calculate the GPIO number XX:
XX = linux gpio number = (gpio_bank - 1) * 32 + gpio_bit