我正在尝试使用getline（）接收输入后从用户输入标记字符串 . 我的代码如下 . 但是，一旦我开始标记化，我就会遇到分段错误 . 我应该采用不同的方式进行令牌化，还是我在进行令牌化错误？

int main(int argc, char **argv)
{
  int bytes_read = 1;
  int nbytes = 10;
  char *command, *flag, *pathname, *linkname;
  struct stat st = {0};
  char *cmd = NULL;
  char *token; //Pointer
  int counter = 1; //Counter variable
  FILE *fp;
  char mode2[] = "0750"; //To set the permission of a file/path
  long j;
  char mode[] = "0640"; //To set the permission of a file/path
  long i;

  cmd = (char *) malloc(nbytes+1);
  bytes_read = getline(&cmd, &nbytes, stdin);

  if(bytes_read == -1) {
    puts("Error with command input.\n");
    exit(EXIT_FAILURE);
  }

  //User input is tokenized to determine the proper commands are entered and executed
  token = strtok(cmd, " "); //Input is tokenized by white spaces.

  if(token == NULL)
  {
  printf("Error with command input.\n");
  exit(EXIT_FAILURE);
  }

  token = strtok(cmd, " ");
  if(token != NULL)
      strcpy(flag, token);

  token = strtok(cmd, " ");
  if(token != NULL)
      strcpy(pathname, token);

  token = strtok(cmd, " ");
  if(token != NULL)
      strcpy(linkname, token);
c getline strtok