WMI wildcards and filtering

A question on the forum asking about filtering WMI results raises a number of interesting points.

The user wanted to pass a computername and a filter term to pull product information from remote machines. I ended up with this

$computername = $env:COMPUTERNAME
$filter = ‘Live’

$scriptblock = {
    param($filter)
    Get-WmiObject -Class Win32_product -Filter “Name LIKE ‘%$filter%'” |
    Select  IdentifyingNumber, Name, LocalPackage }

Invoke-Command -ComputerName $computername -ScriptBlock $scriptblock -ArgumentList $filter

You can pass an argument into the scriptblock you use with invoke-command by using the –Argumentlist parameter.

More interesting is the –Filter parameter on Get-Wmi-Object

-Filter “Name LIKE ‘%$filter%'”

Notice that % is the wildcard not * as you’d use for a string.  Its always better to filter the results from Get-WmiObject using –Filter rather than a where-object after the call.

Of course you can just use the wmi or cim cmdlets directly for this problem which is even better

Get-WmiObject -Class Win32_Product -ComputerName $computername -Filter “Name LIKE ‘%$filter%'” | Select  IdentifyingNumber, Name, LocalPackage

Get-CimInstance -ClassName Win32_Product -ComputerName $computername -Filter “Name LIKE ‘%$filter%'” | Select  IdentifyingNumber, Name, LocalPackage

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This entry was posted in CIM, PowerShell and CIM, PowerShell and WMI, Powershell Basics. Bookmark the permalink.

One Response to WMI wildcards and filtering

  1. It’s probably worth adding that you can use these filters with the WQL (SQL-like) query option on both of these cmdlets. So:

    Get-CimInstance -Query “Select * From Win32_Product Where Name Like ‘%$filter%'”

    This allows further efficiencies as you can also specify the specific attributes you want returned:

    Get-CimInstance -Query “Select IdentifyingNumber, Name, LocalPackage From Win32_Product Where Name Like ‘%$filter%'”

    Cheers,
    Chris

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