string pathRead = @"e:\File\test.txt";
string s=null;
if (File.Exists(pathRead))
{
    StreamReader read = new StreamReader(pathRead, System.Text.Encoding.Default);
    Console.WriteLine(s=read.ReadToEnd());
                
}
string pathWrite = @"E:\File\test2.txt";
if (!File.Exists(pathWrite))
{   
    FileInfo file = new FileInfo(pathWrite);
    file.Delete();
    file.Create();
}
StreamWriter write = new StreamWriter(pathWrite);
write.Write(s);
write.Close();