Tool for displaying current number of lines in every script hold in "Assets/Scripts/" directory.

LineCounter.cs

using System.Collections.Generic;
using System.IO;
using System.Linq;
using UnityEditor;
using UnityEngine;

/// <summary>
/// Tool for displaying current number of lines in every script hold in "Assets/Scripts/" directory.
/// </summary>
public class LineCounter : EditorWindow
{
    [SerializeField]
    private bool autoRefresh = true;

    private Vector2 scrollPosition = Vector2.zero;
    private List<(string, int)> filesAndLines = new();
    private int totalLines;
    private int totalFiles;

    #region Unity events

    [MenuItem("Tools/Line Counter")]
    private static void ShowWindow()
    {
        var window = GetWindow<LineCounter>();
        window.titleContent = new GUIContent("Line Counter");
        window.Show();
    }

    private void Awake()
    {
        if (autoRefresh)
        {
            UpdateStats();
        }
    }

    private void OnProjectChange()
    {
        if (autoRefresh)
        {
            UpdateStats();
        }
    }

    private void OnGUI()
    {
        if (GUILayout.Button("Refresh"))
        {
            UpdateStats();
        }
        autoRefresh = EditorGUILayout.ToggleLeft("Auto refresh (can impact performance)", autoRefresh);
        GUILayout.Label($"Total: {totalLines} lines in {totalFiles} files", new GUIStyle
        {
            fontStyle = FontStyle.Bold,
            margin = new RectOffset(5, 5, 5, 5)
        });
        scrollPosition = EditorGUILayout.BeginScrollView(scrollPosition, 
            GUILayout.ExpandHeight(true), GUILayout.ExpandWidth(true));
        foreach (var tuple in filesAndLines)
        {
            GUILayout.Label($"{tuple.Item1}: {tuple.Item2}");
        }
        EditorGUILayout.EndScrollView();
    }

    #endregion

    private void UpdateStats()
    {
        var scriptFiles = new DirectoryInfo(Application.dataPath + "/Scripts")
            .GetFiles("*.cs", SearchOption.AllDirectories);

        filesAndLines.Clear();
        totalLines = 0;
        totalFiles = scriptFiles.Length;

        foreach (var scriptFile in scriptFiles)
        {
            var numLines = File.ReadAllLines(scriptFile.FullName).Length;
            filesAndLines.Add((scriptFile.Name, numLines));
            totalLines += numLines;
        }

        filesAndLines = filesAndLines.OrderByDescending(tuple => tuple.Item2).ToList();
    }
}