Arduino Scetch to display what´s coming on the serial port

displayserial

#include <LiquidCrystal.h>

LiquidCrystal lcd(12,11,5,4,3,2);

char commandbuffer[100];

int readserial()
{
  int i=0;

  if(Serial.available()){
     delay(100);
     while( Serial.available() && i< 99) {
        commandbuffer[i++] = Serial.read();
     }
     commandbuffer[i++]='\0';
  }
  return i;
}

void setup()
{

  Serial.begin(9600);
  Serial.flush();
  
  lcd.begin(16, 2);
  lcd.clear();

  lcd.print("Hei!");
}

void loop()
{
  lcd.setCursor(0,0);
  int i = readserial();
    if(i>0){
     lcd.clear();
     lcd.print((char*)commandbuffer);
   }
     
  delay(100);
 
}