Get the script name from game object

I am not sure what do you mean by "I want to get the name of second script from first script", but take a look at this:

I have to scripts attached to Main Camera gameObject.

Here is the code of Test.cs:

using UnityEngine;
using System.Collections;

public class Test : MonoBehaviour 
{

    void Start()
    {
        MonoBehaviour[] scripts = this.GetComponents<MonoBehaviour> ();

        foreach (MonoBehaviour mb in scripts)
        {
            Debug.Log (mb.GetType ().Name);
        }
    }
}

On start it prints the names of all MonoBehaviours on it:

This, while not straight-forward is a fairly easy way to do what you need.

Since AddComponent no longer accepts a string (the docs indicate otherwise, but I assume it's because Unity hasn't gotten around to update it), what you can do is

1. Get the Type using Type.GetType
2. Use AddComponent(System.Type)

Code below

var type = Type.GetType("SomeClassName");
gameObject.AddComponent(type);