Replace the string in a list that are same with start string

assuming you have the input as List<string> input then this code should work:

  var splittet = input.Select(i => i.Split("\\".ToCharArray(),  StringSplitOptions.RemoveEmptyEntries));

  Action<string[], int> print = (string[] lst, int index) => Console.WriteLine("\\" + string.Join("\\", lst.Skip(index)));

  splittet.Aggregate(new string[] { },
    (common, item) =>
    {
      var index = Enumerable.Range(0, Math.Min(common.Length, item.Length)).FirstOrDefault(i => common[i] != item[i]);
      print(item, index);
      return item;
    }
    );

So given the input

var input = new List<string> { @"\1925\10\04\issue1",
@"\1925\10\05\issue1",
@"\1925\10\07\issue1",
@"\1925\10\10\issue1",
@"\1925\10\11\issue1",
@"\1925\10\12\issue1",
@"\1925\10\04\issue1",
@"\1925\10\04\issue2",
@"\1925\10\04\issue3",
@"\1925\10\04\issue4"};

this is the output:

\1925\10\04\issue1
\05\issue1
\07\issue1
\10\issue1
\11\issue1
\12\issue1
\04\issue1
\issue2
\issue3
\issue4

Some explanation:

First instead of working with a list of string, I split it up to a list of tokens.

Then I defined some print-action. you could instead add the result to an output-list or do whatever. In this case, it is just writing to console

then the list is aggregated. the aggreagtor starts with an empty string-array. then it tries to find the first index, where the first item differs from the emtpy list and prints all parts from this index on. and then the first index is returned to the aggregator. The aggregator then compares this first item with the second item, finds the first index where the parts differ and prints the parts from there on etc etc.