Get-ADComputer | Get-Process - powershell

Question

When I run this:
Get-Process -name csrss -ComputerName (
Get-AdComputer -Filter {
(name -eq "gate") -or (name -eq "client")
} | Select-Object -ExpandProperty name
) | Select-Object Name,MachineName
or
Get-Process -name csrss -ComputerName gate,client | Select-Object Name,MachineName
I get selected processes from the two computers:
Name MachineName
---- -----------
csrss CLIENT
csrss GATE
csrss CLIENT
csrss GATE
But when I run this:
Get-AdComputer -Filter {(name -eq "gate") -or (name -eq "client")} |
Select-Object #{Name='computername';Expression={$_.name}} |
Get-Process -name csrss |
Select-Object name,machinename
I get this output:
Name MachineName
---- -----------
csrss GATE
csrss GATE
If i change name client to DC (it's a localhost) it shows processes only from DC. And it doesn't matter in which order I type the computer names (GATE first or DC first).
Even if I type this:
Get-AdComputer -Filter * |
Select-Object #{Name='computername';Expression={$_.name}} |
Get-Process -name csrss |
Select-Object name,machinename
I get output only from one machine (DC=localhost):
Name MachineName
---- -----------
csrss DC
csrss DC
Why does this happen? Why do I get processes only from one machine?
I can't get the logic, how Get-Process is getting ComputerName in the third case.

Answer 1

You are having difficulties because Get-ADComputer is returning two objects rather than one object with a two value array for computername. Here are four scenarios to illustrate the difference:
# One Object, two value property
[pscustomobject]#{computername="GATE","CLIENT"} |
Get-Process csrss
# Two Objects, one value property
[pscustomobject]#{computername="GATE"},[pscustomobject]#{computername="CLIENT"} |
Get-Process csrss
# Two Objects, one value property using a ForEach-Object
[pscustomobject]#{computername="GATE"},[pscustomobject]#{computername="CLIENT"} |
ForEach-Object { Get-Process csrss -Computername $_.Computername}
# Two Objects, one value property using a ForEach-Object with a nested pipe
[pscustomobject]#{computername="GATE"},[pscustomobject]#{computername="CLIENT"} |
ForEach-Object { $_ | Get-Process csrss}
Applying this concept to your code would look like this:
Get-AdComputer -Filter {(name -eq "gate") -or (name -eq "client")} |
Select-Object #{Name='computername';Expression={$_.name}} |
ForEachObject {
Get-Process -name csrss -Computername $_.Computername |
Select-Object name,machinename
}
Or alternatively using the pipeline inside the ForEach-Object
Get-AdComputer -Filter {(name -eq "gate") -or (name -eq "client")} |
Select-Object #{Name='computername';Expression={$_.name}} |
ForEachObject { $_ |
Get-Process -name csrss |
Select-Object name,machinename
}