function Write-Log {
  param (
      [string]$Message,
      [string]$LogPath = "$env:TEMP\getscancab.log"
    )
  $timestamp = Get-Date -Format "yyyy-MM-dd HH:mm:ss"
  $entry = "[$timestamp] $Message"
  Add-Content -Path $LogPath -Value $entry
}
$LogPath = "<ログの保存先パス>\getscancab.log"

Write-Log -Message "Check the latest wsusscn2.cab." -LogPath $LogPath

$scancabCurrent = "<更新カタログファイルの保存先パス>\wsusscn2.cab"
$scancabTemp = "$env:TEMP\wsusscn2.cab"

#https://go.microsoft.com/fwlink/?LinkID=74689
# -> https://catalog.s.download.windowsupdate.com/microsoftupdate/v6/wsusscan/wsusscn2.cab
Invoke-WebRequest -uri https://go.microsoft.com/fwlink/?LinkID=74689 -outfile $scancabTemp -UseBasicParsing

if (Test-Path $scancabCurrent) {
  if ((Get-Item $scancabTemp).Length -eq (Get-Item $scancabCurrent).Length) {
    Remove-Item $scancabTemp -Force
    Write-Log -Message "Current wsusscn2.cab is up-to-date." -LogPath $LogPath
  } else {
    Remove-Item $scancabCurrent -Force
    Move-Item -Path $scancabTemp -Destination $scancabCurrent
    Write-Log -Message "Updated to the latest wsusscn2.cab." -LogPath $LogPath
  }

} else {
  Move-Item -Path $scancabTemp -Destination $scancabCurrent
  Write-Log -Message "Downloaded to the latest wsusscn2.cab." -LogPath $LogPath
}