text: #include <stdio.h>
  #include <fcntl.h>
  
  int main() {
      int fd;
      char *s;
      fd = open("file", O_WRONLY | O_CREAT | O_TRUNC, 0666);
      dup2(fd, 1);
      close(fd);
      printf("Hello %d\n", fd);
      return 0;
  }
  