// Prints "Windows XP Service Pack 3 (5.1.2600)" on Windows XP SP3

print (SystemInfo.operatingSystem);

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
void Awake() {
print(SystemInfo.operatingSystem);
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

def Awake():
print(SystemInfo.operatingSystem)