Initialize raw disks in Windows, partition, format and assign drive letters

initialize-raw-disks.ps1

$rawdisks = gwmi win32_diskdrive | where {$_.partitions -eq 0}
foreach ($r in $rawdisks)
{
    $available=ls function:[d-z]: -n | ?{ !(test-path $_) } | SELECT -First 1
    $diskIndex = $r.Index
    Write-Host "Initializing Disk $diskIndex as $available. This will take a while."
    (echo "list disk
    select disk $diskIndex
    online disk
    attributes disk clear readonly
    clean
    create partition primary
    select partition 1
    active
    FORMAT FS=NTFS
    ASSIGN LETTER=$available
    EXIT
    ") | diskpart
    Start-Sleep -Seconds 10
}