Using GetComponent to get a script

So I’m trying to access a script using GetComponent, but I’m not sure how.

This was originally apart of a Unity 3D scene but now I’m trying to convert the code over to 2D. At first I was using the default Platform Input Controller to control my character, but I ended up making a new controller script from scratch. So that means I should be trying to reference the script. But apparently the “Script” reference does not exist. Because of that, I am at a loss on how to reference the script.

(here are the relevant parts of said script)

#pragma strict

var ChController : Transform; 
var elevator : Transform;
var climbNow : boolean = false;
var isClimbing : boolean = false;
var heightFactor : float = 3.0;
var speed : float;
private var PlatInput : PlatformInputController; 

function Start () {
	PlatInput = GetComponent("CharacterControlTest");
}

function OnTriggerEnter(Col : Collider){
	if(Col.gameObject.tag == "Climber" /*&& Input.GetKey("e")*/){
		PlatInput.enabled = false;
		if (Col.attachedRigidbody) {
			Col.attachedRigidbody.isKinematic = false;
		}
		climbNow = !climbNow;
	}
}

function OnTriggerStay(Col : Collider){
	if(Col.gameObject.tag == "Climber"){
		if (Col.attachedRigidbody) {
			Col.attachedRigidbody.isKinematic = true;
		}
	print("stop");
	isClimbing = false;
	}
}

function OnTriggerExit(Col : Collider){
	if(Col.gameObject.tag == "Climber"){
		PlatInput.enabled = true;
		Col.attachedRigidbody.isKinematic = false;
		climbNow = false;
	}
}

The component returned by GetComponent needs to be of the same type as the variable it is assigned to.

private var PlatInput : CharacterControlTest; 
 
 function Start () {
     PlatInput = GetComponent("CharacterControlTest");
}

or

private var PlatInput : CharacterControlTest; 
 
 function Start () {
     PlatInput = GetComponent("CharacterControlTest");
}