处理等待输入，获取所有标准输出？ - Visual Basic

Question

我有一个ssh进入Unix服务器的进程。如果给出错误的凭据，我试图获得此过程的标准输出。在这种情况下，程序等待用户输入正确的密码（表示作为参数给出的密码无效）。预期的结果是以下字符串：

Using keyboard-interactive authentication. Password:

我知道这是预期的，因为我已经将标准输出传送到文件，在命令行中运行程序。但是，我遇到了一个问题，无论出于何种原因，标准输出只会给我第一行，然后挂起。它打印出Using keyboard-interactive authentication，但没有到达Password:

这是我的代码：

Dim stdOutput = New StringBuilder()

Public Sub startProcess(processName As String, id As String, unixServer As String, pw As String) 

    Dim process As Process = New Process()
    process.StartInfo.FileName = processName
    process.StartInfo.Arguments = "-ssh " & id & "@" & unixServer & " -pw " & pw
    process.StartInfo.UseShellExecute = False
    process.StartInfo.CreateNoWindow = True
    process.StartInfo.RedirectStandardOutput = True


    AddHandler process.OutputDataRecieved, AddressOf outputHandler
    process.Start()
    process.BeginOutputReadLine()
    'Wait for 3 seconds to give the process a chance to get the standard output
    process.WaitForExit(3000)
    Console.WriteLine(stdOutput.ToString())

End Sub

Public Sub outputHandler(process As Object, outline As DataReceivedEventArgs)
    stdOutput.Append(outline.Data)
End Sub

这只会打印出Using keyboard-interactive authentication.，但不会打印出来Password:感谢任何帮助。