PowerShell 保存标准输出并显示标准输出

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。在该过程结束时，我将结果通过电子邮件发送给我。我还喜欢（有时）观察 PowerShell 窗口以密切关注它，并在处理过程中观察备份的状态。由于我的代码现在就在，stdout 将用于控制台，仅此而已。

我的问题： 是否可以让标准输出进入控制台，并将其保存到变量中以供以后处理？

您可以看到我正在尝试使用 $output 变量，但无济于事。这是 $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

这是我的代码：

（并且从你们那里的所有专家那里稍微主动一点，是的，我使用此代码做了很多工作以输出到文件和标准输出，因此我可以关注所有内容。本节只是一个 sn -p 整个文件。）

###############################
## 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 - 设置这些时，输出将显示在控制台上。

这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 - 您可以打开 $LASTEXITCODE - 例如

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

Answer 2

为什么不把它作为后台作业运行呢？然后，您可以使用 Receive-Job 来获取输出（如果您使用 -Keep，则可以任意多次，并使用它做任何您想做的事情。