getting substrings from string in Arduino

Question

I am trying to get 3 substrings from a Serial String input using space as the delimiter. I tried converting the string input to a char array and using strtok but it didn't work. This was my code;

char buf[100];
char par1[10], par2[10], par3[10];
char del[] = " ";
String command;

void setup() {
Serial.begin(9600);
}

void loop() {
if (Serial.available() > 0) {
command = Serial.readStringUntil('\n');
  command.toCharArray(buf, sizeof(buf));
  
  
  par1 = strtok(buf, del);
  buf = strtok(NULL, del);
  par2 = strtok(buf, del);
  buf = strtok(NULL, del);
  par3 = strtok(buf, del);
  printf("%s %s %s", par2, par2, par3);

 }
 }

How do I do this?