## powershell -NoProfile -ExecutionPolicy Bypass -File xmlupdate.ps1 XMLファイル名
 
param(
  [Parameter(Mandatory = $true)]
  [string] $InputPath
)

if (Test-Path $InputPath) {
    $dir  = (Get-Location).Path
    $base = [System.IO.Path]::GetFileNameWithoutExtension($InputPath)
    $OutputPath = [System.IO.Path]::Combine($dir, ($base + ".new.xml"))
} else {
    Write-Host "ファイルなし"
    exit
}

## 整形用にインデントを指示
$settings = New-Object System.Xml.XmlWriterSettings
$settings.Indent = $true

## XML読み込み
$xmldoc = New-Object System.Xml.XmlDocument
$xmldoc.Load($InputPath)

## ノード修正
$node = $xmldoc.SelectSingleNode("/root/items/item[@id='005RD']")
if ($node -ne $null) {
  $node.InnerText="アイテムX"
  $node.SetAttribute("id", "005X")
}

## ノード追加
$node = $xmldoc.SelectSingleNode("/root/items")
if ($node -ne $null) {
  $itemdoc = $xmldoc.CreateElement("item")
  $itemdoc.InnerText="アイテム7Z"
  $itemdoc.SetAttribute("id","007Z")
  [void] $node.AppendChild($itemdoc)
}

## 修正結果書き出し
$writer = [System.Xml.XmlWriter]::Create($OutputPath, $settings)
$xmldoc.Save($writer)
$writer.Close()