DouKaku?

static void ls(string[] pathList, string path)
{
    int i;
    Console.WriteLine(
        pathList.Where( x => x.IndexOf(path) != -1 )
                .Select( x => x.Substring( path.Length, (i = x.IndexOf( "/", path.Length )) == -1 ? x.Length-path.Length : i-path.Length+1 ) )
                .Aggregate(new StringBuilder(), (sb, s) => sb.Append(s).Append(" "))
    );
}