通过PowerShellPlus示例脚本学习PowerShell-读取VMware主机信息

## =====================================================================
## Title       : GetVI-HostList
## Description : Retrieve VMware Hosts
## Author      : Idera
## Date        : 9/11/2008
## Input       : -VIserver : Virtual Infrastructure server
##                -verbose -debug   
## Output      : VMs
## Usage       : PS> .\GetVI-HostList -VIserver myVIserver -verbose -debug
## Notes       : 
## Tag         : PowerShell, VMware
## Change log  : 
##  4/1/2009 - Added input parameters and trap
##  4/1/2009 - Added Read-Host input prompts and Write-Verbose and Write-Debug statements
## ===================================================================== 

param
(
   [string]$VIserver = "$(Read-Host 'VI Server' [e.g. vs01])",
   [switch]$verbose = $true,
   [switch]$debug = $false
)

function main()
{
   if ($verbose) {$VerbosePreference = "Continue"}
   if ($debug) {$DebugPreference = "Continue"}

	Write-Verbose "Retrieve VMware Hosts..."
	CheckVIToolKit
	GetVI-HostList $VIserver 
}

function GetVI-HostList($VIserver)
{
	trap [Exception] 
	{
		write-error $("TRAPPED: " + $_.Exception.Message);
		continue;
	}

	# Clear Screen
	Clear-Host
	
	# Warn user they must be logged on with an account that has connection rights to the VI server.
	$answer = Read-Host "`n`n`n`tNOTE: You must be logged on with an account that has connection rights to the VI server. `n`n`n`n`tPress <X> to exit, <C> to continue if you have a connection to a VI Server already or <Enter> to continue. "
	if($answer -eq "x")
	{
		break
	}
	else
	{
		if($VIserver -eq "")
		{
			Write-Host "`n`n`n`tERROR- A VI server must be specified!`n`n" -foregroundcolor red
			Read-Host "`n`t Press <Enter> to continue "
			break
		}
		else
		{
			if($answer -eq "C")
			{
				# do nothing as we have a connection we can use already
			}
			else
			{
				Connect-VIServer $VIserver
				Write-Host "`n`n`t You have connected to Server: $VIserver.Name with a SessionID of: $VIserver.SessionID ."
				Read-Host "`n`t Press <Enter> to continue "
			}
		}
		
		Clear-Host
			
		# Display the list of Hosts found on the network.
		Get-VMHost
		Read-Host "`n`n`t Press <Enter> to continue "
	}
} # EOF: GetVI-HostList()

function CheckVIToolKit()
{
	# Before we do anything we must check to see if the user has the VI toolkit installed.
	# If user does not then we prompt the user and exit.
	$Error.Clear()
	Get-PSSnapin vmware*
	if($Error.Count -ne 0)
	{
		Clear-Host
		Write-Host "`n`n`t`t ERROR - To run this script, the VI Toolkit must be installed and registered with Powershell. If the VI Tollkit is installed," -foregroundcolor red -backgroundColor yellow
		Write-Host "`t`t go to the Settings menu in Powershell Plus and click on Manage Snapins." -foregroundcolor red -backgroundColor yellow
		Read-Host  "`n`n`t Press <Enter> to continue."
		Clear-Host
		break
	}
}# EOF: CheckVIToolKit()

main

这个脚本检索VMWare主机，首先看到执行时会执行第81行的CheckVIToolKit，该方法是检索是否安装模拟，使用的一个新Cmdlets是第86行的Get-PSSnapin。

Get-PSSnapin cmdlet 获取 Windows PowerShell 管理单元，这些单元已添加到当前会话中或已在系统上注册它们。 按照检测到的顺序列出这些管理单元。

Get-PSSnapin仅获取已注册的管理单元。

这里主要检测是否安装Vmware模块。（如果没安装可以使用命令

Install-Module VMWare.PowerCLI

来安装）。

第67和76行的Cmdlet都是需要安装VMware的PowerShell模块后才会有的命令。