Question

我想将PowerShell命令的stderr输出存储在变量中。我不想将其存储在文件中，我不想包含标准输出，只是错误输出。

重定向到名为error.txt的文件：

＆安培; $ command $ params 2＆gt; error.txt

这会将stderr和stdout重定向到$ output变量：

$ output =＆amp; $ command $ params 2＆gt;＆amp; 1

但我想将仅错误输出存储在一个变量中（与上面的error.txt文件的内容相同），而无需向文件写入任何内容。我该怎么做？

Answer 1

您可以以稍微不同的方式调用该命令，并使用PowerShell中的-ErrorVariable参数：

Invoke-Expression "$command $params" -ErrorVariable badoutput

$badoutput现在将包含错误字符串的内容。

Answer 2

这是Simon Wahlin使用子表达式的更简单的解决方案

<块引用>

$output = & $command $params 2>&1

应该是：

$errOutput = $( $output = & $command $params ) 2>&1

Answer 3

要添加到arco444，可以使用$badoutput[0].Exception获取特定的例外。

-ErrorAction and -ErrorVariable 提供了有关有效使用PowerShell内置的ErrorAction和ErrorVariable参数的更多信息。

以下是显示此工作的最简单方法：

PS> Stop-Process 13,23
Stop-Process : Cannot find a process with the process identifier 13.
At line:1 char:13
+ Stop-Process  <<<< 13,23
Stop-Process : Cannot find a process with the process identifier 23.
At line:1 char:13
+ Stop-Process  <<<< 13,23

PS> Stop-Process 13,23 -ErrorAction Stop  # Only 1 error
Stop-Process : Command execution stopped because the shell variable “ErrorA
ctionPreference” is set to Stop: Cannot find a process with the process ide
ntifier 13.
At line:1 char:13
+ Stop-Process  <<<< 13,23 -ErrorAction Stop  # Only 1 error

PS> Stop-Process 13,23 -ErrorAction silentlycontinue  # No errors

PS> Stop-Process 13,23 -ErrorAction inquire  # ASK
Confirm
Cannot find a process with the process identifier 13.
[Y] Yes  [A] Yes to All  [H] Halt Command  [S] Suspend  [?] Help
(default is “Y”):h
Stop-Process : Command execution stopped because the user selected the Halt
 option.
At line:1 char:13
+ Stop-Process  <<<< 13,23 -ErrorAction inquire  # ASK
PS>
PS>
PS> Stop-Process 13,23 -ErrorVariable a -ErrorAction SilentlyContinue

PS> $a[0]
Stop-Process : Cannot find a process with the process identifier 13.
At line:1 char:13
+ Stop-Process  <<<< 13,23 -ErrorVariable a -ErrorAction SilentlyContinue

PS> $a[0] |fl * -Force

Exception             : Microsoft.PowerShell.Commands.ProcessCommandExcepti
                        on: Cannot find a process with the process identifi
                        er 13.
TargetObject          : 13
CategoryInfo          : ObjectNotFound: (13:Int32) [Stop-Process], ProcessC
                        ommandException
FullyQualifiedErrorId : NoProcessFoundForGivenId,Microsoft.PowerShell.Comma
                        nds.StopProcessCommand
ErrorDetails          :
InvocationInfo        : System.Management.Automation.InvocationInfo

PS> $a |ft TargetObject -force -auto
TargetObject
————
          13
          23

现在有一件事对人们来说并不明显，你可以在ErrorVariable的变量名前面指定一个“+”，我们会将错误添加到该变量中。

PS> $err=@()
PS> stop-process 13 -ea silentlycontinue -ErrorVariable err
PS> $err.count
1

PS> stop-process 23 -ea silentlycontinue -ErrorVariable +err
PS> $err.count
2
PS> $err
Stop-Process : Cannot find a process with the process identifier 13.
At line:1 char:13
+ stop-process  <<<< 13 -ea silentlycontinue -ErrorVariable err
Stop-Process : Cannot find a process with the process identifier 23.
At line:1 char:13
+ stop-process  <<<< 23 -ea silentlycontinue -ErrorVariable +err

最后，您不需要键入-ErrorAction或-ErrorVariable，我们为这些定义了参数别名，因此您只需键入–EA和-EV。

如何仅在PowerShell中的变量中捕获错误输出

3 个答案: