get-DriveUsage.ps1

# ドライブの使用状況を取得する
$diskUsage = Get-WmiObject Win32_LogicalDisk | Where-Object { $_.DriveType -eq 3 } | ForEach-Object {
    [PSCustomObject]@{
        'Drive'        = $_.DeviceID
        'UsedSpaceGB'  = [math]::Round((($_.Size - $_.FreeSpace) / 1GB), 2)
        'FreeSpaceGB'  = [math]::Round(($_.FreeSpace / 1GB), 2)
        'TotalSpaceGB' = [math]::Round(($_.Size / 1GB), 2)
    }
}

# Out-GridView で結果を表示する
$diskUsage | Out-GridView -Title "Disk Usage"