#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>

int main(int argc, char const *argv[])
{
    int fd;
    char status = 0;

    if (argc != 3) {
        printf("Usage: %s <dev> <on|off>\r\n", argv[0]);
        printf("   eg: %s /dev/led_jzh on\r\n", argv[0]);
        printf("   eg: %s /dev/led_jzh off\r\n", argv[0]);
        return -1;
    }
    fd = open(argv[1], O_RDWR);
    if (fd < 0) {
        printf("Cannot open %s\r\n", argv[1]);
        return -1;
    }
    if (strcmp(argv[2], "on") == 0) {
        status = 1;
    } else if (strcmp(argv[2], "off") == 0) {
        status = 0;
    } else {
        printf("Invalid argument: %s\r\n", argv[2]);
        close(fd);
        return -1;
    }
    write(fd, &status, 1);
    close(fd);

    return 0;
}