New to Powershell - help understanding pipeline

by scriptwriter3 at 2012-10-08 08:49:17

I am new to Powershell and having trouble working with pipelines. I am trying to get some details about BitLocker encryption status for use in a script.

Step #1
I begin by setting up a WMI connection to the Win32_EncryptableVolume class
$HardDriveEncryption = Get-Wmiobject -namespace root\CIMv2\Security\MicrosoftVolumeEncryption -class Win32_EncryptableVolume -Filter “DriveLetter=‘C:’“

Step #2
The next step is to get the VolumeKeyProtectorID values (as output) from the GetKeyProtectors method

The output from this command is
VolumeKeyProtectorID : {{314E8035-4B7C-402C-87C1-9F9B94759E86}, {44DE96F0-8C63-471A-94F1-2B35347433C9}}

Step #3
Using the VolumeKeyProtectorID values as input to the GetKeyProtectorType method I can then get the KeyProtectorType value. The end goal is to get the KeyProtectorType value.

The output from this command is
KeyProtectorType : 1

Now thats all fine and dandy but I need to script this and thats where I am getting lost. I have tried
$HardDriveEncryption.GetKeyProtectors() | $HardDriveEncryption.GetKeyProtectorType("$.VolumeKeyProtectorID")
but that didn’t work. So then I tried
$HardDriveEncryption.GetKeyProtectors() | foreach-object { $HardDriveEncryption.GetKeyProtectorType($
.VolumeKeyProtectorID) }
but that didn’t work either. What am I missing??
by coderaven at 2012-10-08 15:49:51
Your step 1 looks good.

Looking at the output from Step 2 in your process you see 2 {} around the Volume Key Protector IDs. The way I get to pull this data out is using the Select-Object command with -ExpandProperty as follows:

$HardDriveEncryption.GetKeyProtectors() | Select-Object -ExpandProperty VolumeKeyProtectorID

After this you can keep piping but will have to reference the $HardDriveEncryption if you want root level information.
by scriptwriter3 at 2012-10-08 20:08:14
coderaven - thanks for the quick reply and the excellent information!

In case anyone else comes across this post, here is how I combined steps #2 and #3 together

$HardDriveEncryption.GetKeyProtectors() | Select-Object -ExpandProperty VolumeKeyProtectorID | foreach-object { $HardDriveEncryption.GetKeyProtectorType($_) } | Select-Object KeyProtectorType