Question

我对PowerShell中echo和Write-Host之间的区别感到困惑。我有两个文件，POC.ps1＆amp; validatePath.ps1。这些文件在我的本地计算机上，我使用Invoke-Command在远程计算机上运行它们。我使用的是PowerShell v3.0。

要执行这两个脚本，我使用命令：

.\POC.ps1 -filename C:\Users  -user Blaine

以下是两个文件：

POC.ps1：

param($filename, $user)

echo $filename
echo "This"
echo $user

$responseObject = Invoke-Command testcomputer -FilePath .\validatePath.ps1  -ArgumentList($filename, $user) -AsJob

while($responseObject.State -ne "Completed")
{

}

$result = Receive-Job -Id $responseObject.Id -Keep
echo $result

这是事情变得奇怪的地方......

validatePath.ps1：

Param([string] $filename,
      [string] $user)

function ValidatePath( $filename, $user, $fileType = "container" )
{
    Write-Host "This is the file name: $filename"
    Write-Host "This is user: $user"  <--- Notice I'm using Write-Host here
    $fileExist = $null
    if( -not (test-path $filename -PathType $fileType) )
    {
        throw "$user, the path $filename does not exist!"

    }
    else
    {
         Write-Host "This is the second part"
         echo $filename found!
    }
    Write-Host "This is the third part"
    return $fileExist
}


try
{

    ValidatePath($filename, $user)
}
catch
{
    $e = $_.Exception
    echo $e
}

当我运行上面的脚本时，这是输出：

C:\Users
This
Blaine
This is the file name: C:\Users Blaine
This is user:  <--- Notice where this line is?
This is the second part
This is the third part
C:\Users
Blaine
found!

但是，如果我将validatePath.ps1更改为：

Param([string] $filename,
      [string] $user)

function ValidatePath( $filename, $user, $fileType = "container" )
{
    Write-Host "This is the file name: $filename"
    echo "This is user: $user" <---notice I'm using Echo here
    $fileExist = $null
    if( -not (test-path $filename -PathType $fileType) )
    {
        throw "$user, the path $filename does not exist!"

    }
    else
    {
         Write-Host "This is the second part"
         echo $filename found!
    }
     Write-Host "This is the third part"
    return $fileExist
}


try
{

    ValidatePath($filename, $user)
}
catch
{
    $e = $_.Exception
    echo $e
}

这是输出：

C:\Users
This
Blaine
This is the file name: C:\Users Blaine
This is the second part
This is the third part
This is user: <---- Notice where this line is now?
C:\Users
Blaine
found!

您会注意到“这是用户：”这一行位于不同的位置。为什么是这样？为什么echo的工作方式与Write-Host不同？

更新：

更奇怪的是，如果我像这样两次重新运行脚本：

POC.ps1：

param($filename, $user)

echo $filename
echo "This"
echo $user

$responseObject = Invoke-Command CAPTESTPK01 -FilePath .\validatePath.ps1  -ArgumentList $filename, $user -AsJob

while($responseObject.State -ne "Completed")
{

}

$result = Receive-Job -Id $responseObject.Id -Keep
echo $result


$filename = "C:\saddfasdfj"

#Here I run the command again, using a different file name
$responseObject = Invoke-Command CAPTESTPK01 -FilePath .\validatePath.ps1  -ArgumentList $filename, $user -AsJob

while($responseObject.State -ne "Completed")
{
   if($responseObject.State -eq "Failed")
   {
        echo "Failed"
        $result = Receive-Job -Id $responseObject.Id -Keep
        echo $result
        break
   }
}

$result = Receive-Job -Id $responseObject.Id -Keep
echo $resul

在echo中使用validatePath.ps1时，它会为我提供此输出：

C:\Users
This
Blaine
This is the file name: C:\Users
This is the second part
This is the third part
This is user: Blaine <---- This line is here
C:\Users
found!
This is the file name: C:\saddfasdfj
This is user: Blaine <---- But now it's here, where it should be? Wth?
Blaine, the path C:\saddfasdfj does not exist!

Answer 1

echo是Write-Output的别名，它写入Success输出流。这允许通过管道处理输出或重定向到文件。 Write-Host直接写入控制台，因此无法进一步重定向/处理输出。

Answer 2

echo是Write-Output的别名。在Write-Host直接写入'screen'的地方，Write-Output写入管道。如果管道没有输入其他命令，它最终也会在“屏幕”上结束。您看到的差异是Write-Host直接写入屏幕，其中Write-Output首先通过管道，并在Write-Host之后在屏幕上结束。

使用Write-Output可以将输出管道/重定向到文件或其他命令，而Write-Host则不会。应根据您的需要使用它们。

有关详情，请参阅here。

PowerShell中echo和Write-Host有什么区别？

2 个答案: