$globalVar = 'Global'

function Show-Scope {
    begin {
        $beginVar = 'Begin块变量'
        Write-Host "Begin块访问全局变量: $globalVar"
    }
    process {
        $processVar = 'Process块变量'
        Write-Host "Process块继承Begin变量: $beginVar"
        Write-Host "无法访问Process后续块变量"
    }
    end {
        Write-Host "End块访问Process变量: $processVar"
        $global:newGlobalVar = '新建全局变量'
    }
}

# 执行验证
1..3 | Show-Scope
Write-Host "全局访问新建变量: $newGlobalVar"

function Get-SystemInfo {
    [CmdletBinding()]
    param(
        [Parameter(Mandatory,ValueFromPipeline)]
        [ValidatePattern('^[a-zA-Z]')]
        [string[]]$ComputerName,
        
        [ValidateSet('CPU','Memory','Disk')]
        [string]$Category = 'CPU'
    )
    begin { 
        $results = @()
    }
    process {
        foreach ($computer in $ComputerName) {
            $data = [PSCustomObject]@{
                Computer = $computer
                Status = 'Online'
                $Category = (Get-CimInstance -ClassName Win32_$Category)
            }
            $results += $data
        }
    }
    end {
        $results
    }
}

# 支持三种输入方式
'Server01','Server02' | Get-SystemInfo -Category Memory

Get-Content servers.txt | Get-SystemInfo

Get-SystemInfo -ComputerName (Import-Csv -Path datacenter.csv).Name