Inventorying Computers with AD PowerShell

re: Inventorying Computers with AD PowerShell

NedPyle [MSFT] — Tue, 09 Feb 2010 14:42:39 GMT

And yes, I did find an internal discussion on this, it's a known issue.

I also found this, which is a much better solution than my first workaround:

HOW TO CREATE A FUNCTION TO VALIDATE THE EXISTENCE OF AN AD OBJECT (Test-XADObject)

http://blogs.msdn.com/adpowershell/archive/2009/05/05/how-to-create-a-function-to-validate-the-existence-of-an-ad-object-test-xadobject.aspx

You could use this helper function to verify that an object exists before attempting to run further cmdlets against it.

- Ned

re: Inventorying Computers with AD PowerShell

NedPyle [MSFT] — Tue, 09 Feb 2010 14:36:37 GMT

Hmmm - I am able to reproduce that. Very irritating, I'll see if I can get an answer on that.

As a rather lame workaround, I was able to set the global erroraction and it worked - you could do this in blocks around your 'might not find a computer and that's ok' code.

$errorActionPreference = "SilentlyContinue"

get-adcomputer fdfdfdsfsd

$errorActionPreference = "stop"

More info:

get-help about_preference_variables

re: Inventorying Computers with AD PowerShell

rv-private — Tue, 09 Feb 2010 08:32:01 GMT

I love the AD cmdlets, but one strange behavior I noticed is that error suppression via –erroraction doesn’t do the trick.

e.g. when calling the get-adcomputer cmdlets in association with the name of a none-existing computername, I’d like to avoid an error being thrown, but no way ...

Is this on purpose?

C:\> get-adcomputer dummy -ea silentlycontinue

Get-ADComputer : Cannot find an object with identity: 'dummy' under: 'DC=LABO,DC=LOCAL'.

At line:1 char:15

+ get-adcomputer <<<< dummy -ea silentlycontinue

+ CategoryInfo : ObjectNotFound: (dummy:ADComputer) [Get-ADComputer], ADIdentityNotFoundException

+ FullyQualifiedErrorId : Cannot find an object with identity: 'dummy' under: 'DC=LABO,DC=LOCAL'.,Microsoft.ActiveDirectory.Management.Commands.GetADComputer

re: Inventorying Computers with AD PowerShell

Mike Kline — Thu, 04 Feb 2010 20:53:58 GMT

Really good blog Ned. I've still been going to my favorite tool(adfind) for stuff like this but powershell is definitely another great tool.

For now the Quest cmdlets for where I am...Federal agency that is not yet at 2008 R2 (or even 2008).

By the way is your "bird dog" nickname from the movie Bottle Rocket

Thanks

Mike

re: Inventorying Computers with AD PowerShell

NedPyle [MSFT] — Thu, 04 Feb 2010 18:57:41 GMT

And I updated the post with your point to insure it doesn't get lost in the unread comments. Thanks again.

- Ned

re: Inventorying Computers with AD PowerShell

NedPyle [MSFT] — Thu, 04 Feb 2010 18:51:54 GMT

Your first point is correct and I changed the wording.

To your other main point though: as you can see, this post is designed around introduction to PowerShell for admins. The command-line is already long and cryptic enough to a novice - who is likely uncomfortable enough already - without perfectly forming the front of the pipeline. The amount of efficiency gained here is neglible compared to:

1. The fact that this is showing a rare use inventory and not automation.

2. Folks are getting their feet wet. They will learn filter left, format right.

Thanks for the good feedback,

- Ned

re: Inventorying Computers with AD PowerShell

dloder — Thu, 04 Feb 2010 18:38:56 GMT

The statement "And I stopped asking for the OS version data" is not accurate. The "-Property *" clause causes all properties to be returned. All that happened is that you stopped displaying most of the data. You still asked AD for the data. AD still shipped it over the wire back to you. Powershell just threw it away locally.

The Filter Left, Format Right article from the September 2009 issue of Technet Magazine http://technet.microsoft.com/en-us/magazine/2009.09.windowspowershell.aspx does a decent job of trying to get people to trim the pipeline as early as possible. The same concept holds for the list of property values. You should be using (and informating others to use) both the Property and Filter parameters to trim the output up front and only ask for the data needed.