using System;

using System.Collections.Generic;

using System.Linq;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        // Your CSV to read through

        List<string> exampleStream = new List<string>(){ "This is a test                 12 Apr 15 12:12 123.csv","This is a derp                 11 Feb 11 11:11 567.csv"};

        List<string> list = new List<string>();

        foreach(var r in exampleStream)

        {

             // Grab your current string

             var currentLine = r;

             // Split it on multiple occuring strings (at least 12)

             var initialSplit = Regex.Split(currentLine,@"\s{12,}");

             // Let's make sure that we have two parts

             if(initialSplit.Length == 2)

             {

                  // We can ignore the first section as it doesn't contain the Date / Time

                  // Split the second section using another Split

                  var innerSplit = initialSplit.Last().Split(' ');

                  // Now we want everything prior to the last index (our Date) 

                  var date = String.Join(" ",innerSplit.Take(innerSplit.Length - 1));

                  // And the last index (our File Name)

                  var filename = innerSplit.Last();

                  // Output accordingly

                  list.Add(String.Format("Date: {0}, File {1}",date,filename));

             }

             else

             {

                  // The line didn't contain at least 12 spaces consecutively - do something (possibly adjust)

             }

        }

        // Output each line

        for(int i = 1; i <= list.Count; i++)

        {

            Console.WriteLine("Line {0}: {1}",i,list[i-1]);

        }

    }

}