Object.StdErr

Dim WshShell, oExec
Set WshShell = CreateObject("WScript.Shell")
Set oExec    = WshShell.Exec("%comspec% /c dire")

Function ReadAllFromAny(oExec)

     If Not oExec.StdOut.AtEndOfStream Then
          ReadAllFromAny = oExec.StdOut.ReadAll
          Exit Function
     End If

     If Not oExec.StdErr.AtEndOfStream Then
          ReadAllFromAny = "STDERR: " + oExec.StdErr.ReadAll
          Exit Function
     End If
     
     ReadAllFromAny = -1
End Function

Dim allInput, tryCount

allInput = ""
tryCount = 0

Do While True

     Dim input
     input = ReadAllFromAny(oExec)

     If -1 = input Then
          If tryCount > 10 And oExec.Status = 1 Then
               Exit Do
          End If
          tryCount = tryCount + 1
          WScript.Sleep 100
     Else
          allInput = allInput & input
          tryCount = 0
     End If
Loop

WScript.Echo allInput

var WshShell = new ActiveXObject("WScript.Shell");
var oExec    = WshShell.Exec("%comspec% /c dire");

function ReadAllFromAny(oExec)
{
     if (!oExec.StdOut.AtEndOfStream)
          return oExec.StdOut.ReadAll();

     if (!oExec.StdErr.AtEndOfStream)
          return "STDERR: " + oExec.StdErr.ReadAll();
     
     return -1;
}

var allInput = "";
var tryCount = 0;

while (true)
{
     var input = ReadAllFromAny(oExec);
     if (-1 == input)
     {
          if (tryCount++ > 10 && oExec.Status == 1)
               break;
          WScript.Sleep(100);
     }
     else
     {
          allInput += input;
          tryCount = 0;
     }
}

WScript.Echo(allInput);