There was an email I wrote to a team member last week. The point behind it was to help the team member determine what service(s) might be running under a certain account. The Get-Service cmdlet has never provided this functionality, so I mentioned that they use the Win32_Service WMI class (with Windows PowerShell, of course).
This suggestion led to me write and send them a list of command examples to include local vs. remote computers, pulling computer’s from a text file and Csv file, and using Active Directory. It seemed like a fairly solid list, and so I thought it should be posted here. I won’t bother including any output, because it’s fairly easy to figure out what’s going to be returned — the name of the service, the account used to start/run the service, and the remote computer name, in some of the commands that run against remote computers.
This first example is how to run the command against the local computer. This will return all the services on the local computer to include the account that is used to start the listed service.
PS> Get-WmiObject -Class Win32_Service | Select-Object Name,StartName
This example shows how to run the same command above, against a single remote computer. The only difference is the addition of the -ComputerName parameter and the Server01 parameter value.
PS> Get-WmiObject -ComputerName Server01 -Class Win32_Service | Select-Object Name,StartName
In this example, we run the same command above, except we do run it against two computers. In order to know which computer returned which result, we include the PSComputerName property.
PS> Get-WmiObject -ComputerName Server01,Server02 -Class Win32_Service | Select-Object PSComputerName,Name,StartName
Here’s one way to use a text file. The Get-Content cmdlet executes first, because it’s in parenthesis. The results of this command are then provided to the -ComputerName parameter.
PS> Get-WmiObject -ComputerName (Get-Content -Path C:\computers.txt) -Class Win32_Service | Select-Object PSComputerName,Name,StartName
This example does the same thing as the command above; however, it does so by piping the results of the Get-Content cmdlet to the ForEach-Object cmdlet. Within each iteration of the foreach loop, it runs the Get-WmiObject command. In testing, there wasn’t much different in the time it took to complete this example when compared to the last one.
PS> Get-Content -Path C:\computers.txt | ForEach-Object {Get-WmiObject -ComputerName $_ -Class Win32_Service | Select-Object PSComputerName,Name,StartName}
This next example utilizes a Csv File. In a Csv file, we have (column) headers; therefore, we need to indicate to PowerShell the column we’d like to use. Let’s assume we have a Csv with three columns of data with the headers Location, NameOfComputer, and Year. We’ll need to make sure we’re instructing our command to only use the data in the NameOfComputer column.
PS> Get-WmiObject -ComputerName ((Import-Csv -Path C:\computers.csv).NameOfComputer) -Class Win32_Service | Select-Object PSComputerName,Name,StartName
Here’s the same example as above, but this one uses a pipeline and ForEach-Object cmdlet, much like we did with the text file. While there’s little difference in the time it takes to complete, I would recommend that we don’t use a pipe when it’s not necessary, or when it’s doesn’t give us an advantage.
PS> Import-Csv -Path C:\computers.csv | ForEach-Object {Get-WmiObject -ComputerName $_.NameOfComputer -Class Win32_Service | Select-Object PSComputerName,Name,StartName}
Let’s incorporate Active Directory (AD), since it’s another place where we can get computers. This first AD example returns all the computers from a specific Organization Unit (OU) and runs them through the Get-WmiObject cmdlet. As in previous examples, this command will return all the values before it provides them as the value to the -ComputerName parameter.
PS> Get-WmiObject -ComputerName ((Get-ADComputer -Filter * -SearchBase 'OU=Engineering,OU=Workstations,DC=mydomain,DC=com').Name) -Class Win32_Service | Select-Object PSComputerName,Name,StartName
In my coworker’s situation, one of the computers in the OU was down, so we needed a way to filter around that problem. Here’s two ways to do that; however, the second option is the better of the two. If you’ve never heard it before, hear it now: filter as close to the left of your commands as possible.
PS> Get-WmiObject -ComputerName ((Get-ADComputer -Filter * -SearchBase 'OU=Engineering,OU=Workstations,DC=mydomain,DC=com' | Where-Object {$_.Name -ne 'Server22'}).Name) -Class Win32_Service | Select-Object PSComputerName,Name,StartName
PS> Get-WmiObject -ComputerName ((Get-ADComputer -Filter {Name -ne 'Server22'} -SearchBase 'OU=Engineering,OU=Workstations,DC=mydomain,DC=com').Name) -Class Win32_Service | Select-Object PSComputerName,Name,StartName
