Question

我正在使用PowerShell启动名为GoodSync的应用程序来为我执行备份。在流程结束时，我通过电子邮件将结果发送给我。我也喜欢（有时）观看PowerShell窗口以密切关注它并在处理时观察备份的状态。正如我的代码现在所处，stdout将进入控制台，就是这样。

我的问题：是否可以将stdout转到控制台，并将其保存到变量以供以后处理？

你可以看到我正在尝试使用$ output变量，但无处可去。这是$ output输出的错误：

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：

（并且从你所有的大师们那里得到一点主动，是的，我用这个代码做了很多工作，输出到文件和标准输出，所以我可以留意一切。这部分只是一个片段整个文件。）

###############################
## 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，控制台上将显示输出。

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 - 你可以在$LASTEXITCODE上进行切换 - 例如

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

Answer 2

为什么不将它作为后台工作运行？然后你可以使用Receive-Job来获取输出（如果你使用-Keep，你可以多次使用它，并随意做任何事情。

PowerShell保存标准输出并显示标准输出

2 个答案: