Василий Банников

GIT_EDITOR
           This environment variable overrides $EDITOR and $VISUAL.
           It is used by several Git commands when, on interactive mode,
           an editor is to be launched.
           See also git-var(1) and the core.editor option in git-config(1).

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		var path = "file.txt";
		var lines = new string[]{"123456789", "bbbb"};
		// lines = File.ReadAllLines(path);
		string FindSubString(string substring) => lines.FirstOrDefault(x => x.StartsWith(substring));
		var res = FindSubString("1");
		Console.WriteLine(res);
	}
}

public struct MyStruct
{
     public int ID;
     public string FIleName;
}

MyStruct myFile = new MyStruct();
myFile.ID = 1;
myFile.FileName = "File.png";

var dictionary = new Dictionary<string, MyStruct> {
"Файл1" ,  myFile
}