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

int main(int argc, char *arv[]) {
    char *txt = "Hallo Welt";

    int fd = open("test.txt", O_CREAT | O_RDWR, S_IRUSR | S_IWUSR);

    write(fd, txt, 10);
    lseek(fd, 10 * 1024 * 1024, SEEK_CUR);
    write(fd, txt, 10);

    close(fd);
    return 0;
}