button press command.

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define BUTTON_PIN "P8_11"
#define LED_PIN "P8_13"

int main(int argc, char *argv[]) {
    // Export the button and LED pins
    system("echo " BUTTON_PIN " > /sys/class/gpio/export");
    system("echo " LED_PIN " > /sys/class/gpio/export");

    // Set the button pin as an input
    system("echo in > /sys/class/gpio/gpio" BUTTON_PIN "/direction");

    // Set the LED pin as an output
    system("echo out > /sys/class/gpio/gpio" LED_PIN "/direction");

    while (1) {
        // Read the button state
        FILE *button_file = fopen("/sys/class/gpio/gpio" BUTTON_PIN "/value", "r");
        int button_state = fgetc(button_file) - '0';
        fclose(button_file);

        // If the button is pressed, turn on the LED
        if (button_state == 0) {
            system("echo 1 > /sys/class/gpio/gpio" LED_PIN "/value");
        } else {
            system("echo 0 > /sys/class/gpio/gpio" LED_PIN "/value");
        }

        // Wait for a bit before reading the button state again
        usleep(100000);
    }

    return 0;
}