NullReferenceException: Object reference not set to an instance of an object

Im new in unity and im tryin to get familiar to mading scripts so im making a simple scene where the player needs to kill the enemy but in the attack script i get this error: NullReferenceException: Object reference not set to an instance of an object
Target1.attack () (at Assets/Target1.cs:66)
Target1.Update () (at Assets/Target1.cs:37) and i have a problem that when i attack the enemyhealth dont get affected

please help me to find whats happening

here are the scripts


Attack

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
public class Target1 : MonoBehaviour {

public Transform selectedTarget;
public Transform enemy;
public bool Enemy = false;
public Transform myTransform;
public Rigidbody Bala;
public Transform placementspot;

private EnemyHealth enemyHealth;

	void awake (){
		enemyHealth = GetComponent <EnemyHealth>();

	}
	
  void Update(){
    if (Input.GetMouseButtonDown(0)){ // when button clicked...
      RaycastHit hit; // cast a ray from mouse pointer:
      Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
      // if enemy hit...
      if (Physics.Raycast(ray, out hit) && hit.transform.CompareTag("Enemy")){
        DeselectTarget(); // deselect previous target (if any)...
        selectedTarget = hit.transform; // set the new one...
        SelectTarget(); // and select it
		Debug.Log(hit.collider.name);

      }
    }
	if (Enemy == true && Input.GetKeyUp(KeyCode.A)){//attack the enemy
		Rotate();
		Debug.Log ("it hits!");
		attack();
	}
				
		
  }

  	private void SelectTarget(){ 
		enemy = selectedTarget.transform;
		Enemy = true;
  }

	private void DeselectTarget(){
		Enemy = false;
   
    }
			
	private void Rotate (){
		
	myTransform.LookAt (enemy.transform);
		
	}
	
	private void attack (){
		
		Rigidbody clone;//instantiate the bullet
		clone = Instantiate(Bala, placementspot.position, transform.rotation) as Rigidbody;
        clone.velocity = transform.TransformDirection(Vector3.forward * 10);

		EnemyHealth eh = enemyHealth;//addjust the enemy health
		eh.AddjustEnemyHealth(-10);
		
	}
	
}

enemy Health

using UnityEngine;
using System.Collections;

public class EnemyHealth : MonoBehaviour {
	
	public int enemyHealth = 100;
	public int enemyMaxHealth = 100;
	private float healthBarLength;

	// Use this for initialization
	void Start () {
		healthBarLength = Screen.width / 4;
	}
	
	// Update is called once per frame
	void Update () {
		AddjustEnemyHealth(0);
	
	}
	void OnGUI() {
		GUI.Box(new Rect(10, 10, healthBarLength,20), enemyHealth + "/" + enemyMaxHealth);
	}

	public void AddjustEnemyHealth(int adj) {
		enemyHealth += adj;	
		
		if(enemyHealth < 0)
			enemyHealth = 0;
		
		if(enemyHealth > enemyMaxHealth)
			enemyHealth = enemyMaxHealth;
		
		if(enemyMaxHealth < 1)
			enemyMaxHealth = 1;

	}

}

It states that the variable “eh” is null on line 65 (66 in your project according to the error) and therefore you can not call the “AddjustEnemyHealth” function. The “eh” variable gets its value from “enemyHealth” on line 64. This means that “enemyHealth” does not have a value either. “enemyHealth” gets its value in the Awake function on line 16 with a GetComponent function. You have written the Awake function with a lower case ‘A’ so it will not be called by Unity.

Change the function to Awake() with an upper case ‘A’