在PowerShell脚本中处理命令提示符错误 [英] Handle command prompt error within PowerShell script

问题描述

我正在尝试在PowerShell脚本中运行一些命令提示符命令，例如 schtasks 。我想知道如何处理PowerShell中命令所引发的错误。

I am trying to run a few command prompt commands like schtasks within a PowerShell script. I would like to know how to handle errors thrown by the command in PowerShell.

我尝试过：

• & cmd.exe / c’schtasks / Query / TN xx || echo ERROR’


• & cmd.exe / c‘ping.exe 122.1.1.1&&出口0 ||出口1'


• Invoke-Expression -Command：$ command

• & cmd.exe /c 'schtasks /Query /TN xx || echo ERROR'
• & cmd.exe /c 'ping.exe 122.1.1.1 && exit 0 || exit 1'
• Invoke-Expression -Command:$command

我无法运行这些命令，也无法在 try..catch 块中忽略或捕获异常PowerShell脚本。我知道有库，但仅限于PowerShell v2.0。

I'm unable to run these commands and ignore or catch exception in a try..catch block of the PowerShell script. I know there are libraries but I'm limited to PowerShell v2.0.

推荐答案

外部命令通常设置非零退出代码因错误而终止，因此您可以检查自动变量 $ LASTEXITCODE 具有非零值：

External commands usually set a non-zero exit code if they're terminating with an error, so you could check if the automatic variable $LASTEXITCODE has a non-zero value:

& cmd /c 'schtasks /Query /TN xx'
if ($LASTEXITCODE -ne 0) {
  'an error occurred'
}

但是请注意，有些程序使用非零退出代码获取非错误信息（例如 robocopy （使用退出代码低于8的状态信息），或 choice （使用退出代码表示所选的选项）。

Note, however, that there are some programs that use non-zero exit codes for non-error information, (e.g. robocopy, which uses the exit codes below 8 for status information, or choice, which uses the exit code to indicate the chosen option).

可以通过在CMD中重定向错误输出流来抑制外部命令的错误消息：

Error messages of the external command can be suppressed by redirecting the error output stream, either in CMD:

& cmd /c 'schtasks /Query /TN xx 2>nul'

或在PowerShell中：

or in PowerShell:

& cmd /c 'schtasks /Query /TN xx' 2> $null

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