I have a lot of duplicated objects, and I need in editor, not in the game, apply some changes to the objects (remove specific material). Of course I can do this manually, but there are a lot of them.

In case of Javascript, you can just open console, and get all stuff You need by methods like getElementsByClassName. It would be perfect if some similar functionality exist (at least as addons) in Unity.

I do not need some UI for using script currently, and I also do not need to run it on Unity launch. I want to call it every time by pressing some key in editor.

So, seems that I have to enumarate all game objects, get their meshes, check GUID, and if it equals to that I need, then enumarete object's materials list, find by GUID material I need, and call some remove method to it.

Point me where I should look, and should learn to achive that.

I have a lot of duplicated objects, and I need in editor, not in the game, remove specific (18) material slot. Remove not material in slot 18, but remove slot 18. Manually, by hands, it can be done using this button:

All objects that I need to remove slot from has the next mutuals:

1. Contain "_lod" in the name;
2. Have the same mesh, with the same GUID

I did not find how to get GUID of the given object, so the search, probably need to go by name.

I have never scripted Unity, I even did not write in C# (although I write in C++).

What I done so far: I created an empty game object and assign cs script below to it as a component. DestroyImmediate(myMaterials[18]), works almost that I need, but it removes not the slot, but the material on it (and automatically creates default material). I need to remove exactly the slot.

LookAtPoint.cs:

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

using UnityEditor;
[ExecuteInEditMode]

public class LookAtPoint : MonoBehaviour
{
    void Iter(GameObject gameObject) // Itterate children
    {
        for (int j = 0; j < gameObject.transform.childCount; j++) 
        {
            GameObject a = (GameObject)gameObject.transform.GetChild(j).gameObject;
            MeshFilter viewedModelFilter = (MeshFilter)a.GetComponent("MeshFilter");

            if(viewedModelFilter && viewedModelFilter.mesh && a.name.IndexOf("_lod") != -1) // check if object has mesh and it's name contains "_lod"
            {
                Material[] myMaterials = a.GetComponent<Renderer>().materials;
                if(myMaterials[18].name.IndexOf("Подоконник")!=-1) // not neccesary check if 18s slot has "Подоконник" name (actually now it is already "Default-Material")
                {
                    DestroyImmediate(myMaterials[18]);
                }
            }
            Iter(a);
        }
    }

    void Start()
    {
        List<GameObject> rootObjects = new List<GameObject>();
        Scene scene = SceneManager.GetActiveScene();
        scene.GetRootGameObjects( rootObjects );
        
        for (int i = 0; i < rootObjects.Count; ++i)
        {
            GameObject gameObject = rootObjects[ i ]; // get root objects

            for (int j = 0; j < gameObject.transform.childCount; j++) // enumarate them
            {
                Iter(gameObject); // iteratevely process the children 
            }
        }
    }
}