public class ConsoleReader
 {
  public static IEnumerable<string> ReadFromBuffer( short x, short y, short width, short height )
  {
   IntPtr buffer = Marshal.AllocHGlobal( width * height * Marshal.SizeOf( typeof( CHAR_INFO ) ) );
   if ( buffer == null )
    throw new OutOfMemoryException( );
   try
   {
    COORD coord = new COORD( );
    SMALL_RECT rc = new SMALL_RECT( );
    rc.Left = x;
    rc.Top = y;
    rc.Right = (short) ( x + width - 1 );
    rc.Bottom = (short) ( y + height - 1 );
    COORD size = new COORD( );
    size.X = width;
    size.Y = height;
    const int STD_OUTPUT_HANDLE = -11;
    if ( !ReadConsoleOutput( GetStdHandle( STD_OUTPUT_HANDLE ), buffer, size, coord, ref rc ) )
    {
     // ‘Not enough storage is available to process this command‘ may be raised for buffer size > 64K (see ReadConsoleOutput doc.)
     throw new Win32Exception( Marshal.GetLastWin32Error( ) );
    }
    IntPtr ptr = buffer;
    for ( int h = 0; h < height; h++ )
    {
     StringBuilder sb = new StringBuilder( );
     for ( int w = 0; w < width; w++ )
     {
      CHAR_INFO ci = (CHAR_INFO) Marshal.PtrToStructure( ptr, typeof( CHAR_INFO ) );
      char[] chars = Console.OutputEncoding.GetChars( ci.charData );
      sb.Append( chars[0] );
      ptr += Marshal.SizeOf( typeof( CHAR_INFO ) );
     }
     yield return sb.ToString( );
    }
   }
   finally
   {
    Marshal.FreeHGlobal( buffer );
   }
  }
  [StructLayout( LayoutKind.Sequential )]
  private struct CHAR_INFO
  {
   [MarshalAs( UnmanagedType.ByValArray, SizeConst = 2 )]
   public byte[] charData;
   public short attributes;
  }
  [StructLayout( LayoutKind.Sequential )]
  private struct COORD
  {
   public short X;
   public short Y;
  }
  [StructLayout( LayoutKind.Sequential )]
  private struct SMALL_RECT
  {
   public short Left;
   public short Top;
   public short Right;
   public short Bottom;
  }
  [StructLayout( LayoutKind.Sequential )]
  private struct CONSOLE_SCREEN_BUFFER_INFO
  {
   public COORD dwSize;
   public COORD dwCursorPosition;
   public short wAttributes;
   public SMALL_RECT srWindow;
   public COORD dwMaximumWindowSize;
  }
  [DllImport( "kernel32.dll", SetLastError = true )]
  private static extern bool ReadConsoleOutput( IntPtr hConsoleOutput, IntPtr lpBuffer, COORD dwBufferSize, COORD dwBufferCoord, ref SMALL_RECT lpReadRegion );
  [DllImport( "kernel32.dll", SetLastError = true )]
  private static extern IntPtr GetStdHandle( int nStdHandle );
 }

C# read cmd console