PowerShell保存标准输出和显示标准输出

Question

我正在使用PowerShell启动一个名为GoodSync的应用程序来为我执行备份。在过程结束时，我会把结果发电子邮件给我。我还喜欢(有时)观看PowerShell窗口，以监视它，并在处理过程中观察备份的状态。现在，当我的代码处于位置时，stdout将用于控制台，仅此而已。

我的问题：是否可能让stdout转到控制台，并将其保存到一个变量中以供以后处理？

您可以看到，我正在尝试使用$output变量，但一无所获。下面是$output返回的错误：

You cannot call a method on a null-valued expression.
At GoodSync.ps1:119 char:42
+     $output = $proc.StandardOutput.ReadToEnd <<<< ()
    + CategoryInfo          : InvalidOperation: (ReadToEnd:String) [], Runtime
   Exception
    + FullyQualifiedErrorId : InvokeMethodOnNull

You cannot call a method on a null-valued expression.
At GoodSync.ps1:120 char:42
+     $output += $proc.StandardError.ReadToEnd <<<< ()
    + CategoryInfo          : InvalidOperation: (ReadToEnd:String) [], Runtime
   Exception
    + FullyQualifiedErrorId : InvokeMethodOnNull

这是我的密码：

(为了让所有的专家都保持积极主动，是的，我做了大量的工作，将这些代码输出到文件和stdout中，这样我就可以监视所有的事情了。这个部分只是整个文件的一个片段。)

###############################
## Call the GoodSync process ##
###############################

# This is the section taken from http://stackoverflow.com/questions/8925323
# This is a known working section. However, right now I don't know how to save the stdout to variable and insert into email log file.
$procInfo = New-Object System.Diagnostics.ProcessStartInfo
$procInfo.FileName = "C:\Program Files\Siber Systems\GoodSync\gsync.exe"
$procInfo.UseShellExecute = $false
$procInfo.Arguments = '/progress=yes /exit sync MyBackupJobName'
$proc = New-Object System.Diagnostics.Process
$proc.StartInfo = $procInfo
$proc.Start() | Out-Host
(Get-Date -format T) + " - Loaded gsync.exe. Backup process running. Please stand by..." | Tee-Object -Variable RoboLog
$RoboLog >> $myLogFile
"" | Tee-Object -Variable RoboLog
$RoboLog >> $myLogFile
$proc.WaitForExit()
(Get-Date -format T) + " - Backup complete and gsync.exe has exited." | Tee-Object -Variable RoboLog
$RoboLog >> $myLogFile
"" | Tee-Object -Variable RoboLog
$RoboLog >> $myLogFile

# Now we take the exit code, write it to console and log file, and begin to build our email report. 
if ($proc.ExitCode -eq 0) { 
    "Success: GoodSync Reported: Analyze or Sync Successfully Completed." | Tee-Object -Variable RoboLog
    $RoboLog >> $myLogFile
    $subject = $RoboLog
    "" | Tee-Object -Variable RoboLog
    $RoboLog >> $myLogFile
} elseif ($proc.ExitCode -eq 1) {
    "Failure: GoodSync Error: Analyze had Terminal Errors. Did gsync.exe close abruptly?" | Tee-Object -Variable RoboLog
    $RoboLog >> $myLogFile
    $subject = $RoboLog
    "" | Tee-Object -Variable RoboLog
    $RoboLog >> $myLogFile
} elseif ($proc.ExitCode -eq 2) {
    "Failure: GoodSync Error: Sync had Terminal Errors. Did gsync.exe close abruptly?" | Tee-Object -Variable RoboLog
    $RoboLog >> $myLogFile
    $subject = $RoboLog
    "" | Tee-Object -Variable RoboLog
    $RoboLog >> $myLogFile
} else { 
    "Failure: GoodSync Error: General Error. Check log file." | Tee-Object -Variable RoboLog
    $RoboLog >> $myLogFile
    $subject = $RoboLog
    "" | Tee-Object -Variable RoboLog
    $RoboLog >> $myLogFile
}

# Grab the stdout and stderr to a variable
$output = $proc.StandardOutput.ReadToEnd()
$output += $proc.StandardError.ReadToEnd()
# The ReadToEnd() makes everything 1 long string, so we break it up by carriage return, and filter
$output -split "`n"
# Write to log file for email capture
$output >> $myLogFile

"" | Tee-Object -Variable RoboLog
$RoboLog >> $myLogFile

#---------------------------------------------------------------------------------------------------
# GoodSync backup jobs are now complete.
#---------------------------------------------------------------------------------------------------

Answer 1

来自$proc.StandardOutput.ReadToEnd (You cannot call a method on a null-valued expression.)的错误是因为您需要在ProcessStartInfo对象上设置这些属性：

$procInfo.RedirectStandardError = $true
$procInfo.RedirectStandardOutput = $true

注意-当设置这些时，输出将不会显示在控制台上。

下面是一种将输出存储在变量中并使用Tee-Object在控制台上显示的方法

& ping.exe localhost -n 1 | Tee-Object -Variable output
$output

顺便说一句，你可以在$LASTEXITCODE上做一个开关。

switch ($LASTEXITCODE) {
    0 {'good'}
    1 {'bad'}
    2 {'ugly'}
}

Answer 2

为什么不直接把它作为背景工作来运行呢？然后，您可以使用接收-作业来获取输出(如果使用-Keep，可以使用任意次数的输出，并对它做任何您想做的事情。