how to get rid of multiple of spawning at a time in single click. Here when I click single time 5 kunai spawn at a time!

[rkerketta]

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class playerControl : MonoBehaviour
{
	public float speed = 5f;
	private float movement = 0f;
	private Rigidbody2D rigidbody;
	public float jumpForce = 8f;
	public Transform groundCheck;
	public float checkRadious;
	public LayerMask whatIsGround;
	private bool isTouchingGround;
	private Animator playAnimation;

	private bool doubleTap;
	private bool attack=true;
	private bool facingRight;
	public GameObject kunai;

    // Start is called before the first frame update
    void Start()
    {
		facingRight = true;
		rigidbody = GetComponent<Rigidbody2D>();
		playAnimation = GetComponent<Animator>();
    }

    // Update is called once per frame
    void Update()
    {

		//counting click



		isTouchingGround = Physics2D.OverlapCircle (groundCheck.position,checkRadious,whatIsGround);
		//Horizontal movement
		movement = Input.GetAxis ("Horizontal");
		//getting current animation info
		if(!this.playAnimation.GetCurrentAnimatorStateInfo(0).IsTag("attack") && !this.playAnimation.GetCurrentAnimatorStateInfo(0).IsTag("throw")){
			if (movement > 0) {

				rigidbody.velocity = new Vector2 (movement * speed, rigidbody.velocity.y);
				direction (movement);
			} else if (movement < 0) {
				rigidbody.velocity = new Vector2 (movement * speed, rigidbody.velocity.y);
				direction (movement);
			} else {
				rigidbody.velocity = new Vector2 (0,rigidbody.velocity.y);
			}
			if(Input.GetKeyDown(KeyCode.Space) && isTouchingGround){
				rigidbody.velocity = new Vector2 (rigidbody.velocity.x,jumpForce);
			}
		}


		if(Input.GetMouseButton(1) && isTouchingGround){
			playAnimation.SetTrigger ("attack");
			rigidbody.velocity = Vector2.zero;

		}
		if(Input.GetMouseButton(0)&& isTouchingGround){

			playAnimation.SetTrigger ("throw");
			rigidbody.velocity = Vector2.zero; //setting velocity to zero till animation is over
			throwKnife (0);
		}

		playAnimation.SetFloat ("speed",Mathf.Abs(rigidbody.velocity.x));
		playAnimation.SetBool ("glide",isTouchingGround);
    }
	public void throwKnife(int value){
		direction (movement);
		if (facingRight) {
			GameObject tmp = (GameObject)Instantiate (kunai,transform.position,Quaternion.Euler(new Vector3(0,0,-90)));
			tmp.GetComponent<kunai>().Initialize (Vector2.right);
		} else {
			GameObject tmp = (GameObject)Instantiate (kunai,transform.position,Quaternion.Euler(new Vector3(0,0,90)));
			tmp.GetComponent<kunai>().Initialize (Vector2.left);
		}

	}
	private void direction(float movement){
		if(movement>0 && !facingRight ||movement<0 && facingRight){
			facingRight = !facingRight;
			Vector3 theScale = transform.localScale;
			theScale.x *= -1;
			transform.localScale = theScale;
		}
	}

}

[harsh2580]

if(Input.GetMouseButton(0)&& isTouchingGround){

         playAnimation.SetTrigger ("throw");
         rigidbody.velocity = Vector2.zero; //setting velocity to zero till animation is over
         throwKnife (0);
     }

Replace This Line of code with Below one

if(Input.GetMouseButtonDown(0)&& isTouchingGround){

         playAnimation.SetTrigger ("throw");
         rigidbody.velocity = Vector2.zero; //setting velocity to zero till animation is over
         throwKnife (0);
     }

Basically what Input.GetMouseButtonDown does is only receive it when it gets down and the one Input.GetMouseButton that ur using receive input when mouse button being hold
Its Like
1st Input.GetMouseButtonDown - 1 time on down (prerssed)
2nd Input.GetMouseButton - number of time frames passed key holded
3rd Input.GetMouseButtonUp - 1 time on up (released)

@rkerketta