// 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 Example() {
        print(SystemInfo.operatingSystem);
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def Example():
        print(SystemInfo.operatingSystem)