Windows Powershell ForEach-Object 循环

对管道对象逐个处理

如果使用Get-WmiObject 获取系统中的服务，为了排版可能会也会使用Format-Table对结果进行表格排版。

PS C:Powershell> Get-WmiObject Win32_Service | Format-Table status,DisplayName
-AutoSize

status DisplayName
------ -----------
OK     Adobe Acrobat Update Service
OK     Application Experience
OK     Application Layer Gateway Service
OK     Application Host Helper Service
OK     Application Identity
OK     Application Information
OK     Application Management
OK     ASP.NET State Service
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但是如果想对每个服务进行更定制化的处理可是使用ForEach-Object

PS C:Powershell> Get-WmiObject Win32_Service | ForEach-Object {"Name:"+ $_.Disp
layName, ", Is ProcessId more than 100:" + ($_.ProcessId -gt 100)}
Name:Adobe Acrobat Update Service , Is ProcessId more than 100:True
Name:Application Experience , Is ProcessId more than 100:False
Name:Application Layer Gateway Service , Is ProcessId more than 100:False
Name:Application Host Helper Service , Is ProcessId more than 100:True
Name:Application Identity , Is ProcessId more than 100:True
Name:Application Information , Is ProcessId more than 100:True
Name:Application Management , Is ProcessId more than 100:False
Name:ASP.NET State Service , Is ProcessId more than 100:False
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结合条件处理

ForEach-Object的处理可以包含任意Powershell脚本，当然也包括条件语句

Get-WmiObject Win32_Service | ForEach-Object {
    if ($_.ProcessId -gt 3000)
    { "{0}({1})" -f $_.DisplayName,$_.ProcessID}
}
Windows Presentation Foundation Font Cache 3.0.0.0(5408)
Microsoft Network Inspection(5260)
BranchCache(4112)
Windows Modules Installer(7656)
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调用方法

在ForEach-Object中，$_代表当前对象，当然也允许通过$_,调用该对象支持的方法。
下面的例子杀死所有IE浏览器进程：

PS C:Powershell> Get-Process iexplore

Handles  NPM(K)    PM(K)      WS(K) VM(M)   CPU(s)     Id ProcessName
-------  ------    -----      ----- -----   ------     -- -----------
    883      29    14728      22432   181    34.26   4300 iexplore
    771      28    55552     129152   425     8.56   5732 iexplore
   1216      51   104324     143916   539   572.41   5912 iexplore
    801      25    49200      25372   285     5.99   6252 iexplore
    691      25    57564      95796   333     8.08   6388 iexplore
   1256      38    85848     127012   379    20.37   7856 iexplore

PS C:Powershell> Get-Process iexplore | ForEach-Object {$_.kill()}
PS C:Powershell> Get-Process iexplore
Get-Process : 找不到名为“iexplore”的进程。请验证该进程名称，然后再次调用 cmdlet。
所在位置 行:1 字符: 12
+ Get-Process <<<< iexplore
+ CategoryInfo : ObjectNotFound: (iexplore:String) [Get-Process],
ProcessCommandException
+ FullyQualifiedErrorId : NoProcessFoundForGivenName,Microsoft.PowerShell.
Commands.GetProcessCommand
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