gistfile1.cs

public class GameManager : MonoBehaviour
{
	
	public static GameManager instance = null;	
	
	void Awake()
		{
			//Check if instance already exists
			if (instance == null)
				
				//if not, set instance to this
				instance = this;
			
			//If instance already exists and it's not this:
			else if (instance != this)
				
				//Then destroy this. This enforces our singleton pattern, meaning there can only ever be one instance of a GameManager.
				Destroy(gameObject);	
		}