Learn Windows PowerShell3 In a Month of Lunches 2nd Edition Chapter 9 Lab

PowerShell Help
1

I am trying to learn PowerShell using Learn Windows PowerShell3 In a Month of Lunches 2nd Edition

The Chapoter 9 Lab for number 4 had this question:
Write a command that uses pipeline parameter binding to retrieve a list of running processes from every computer in an AD domain.
Don’t use parentheses.

And this was the answer (which was the same answer that I came up with) but I do not think it is working correctly.

get-adcomputer -filter * | Select-Object @{Label=‘computername’;Expression={$_.name}} | Get-Process

Here is the result:

computername

LYNCDC6
LYNCSE6
LYNCEXUM6
MINTZ

from running this part of the command:

get-adcomputer -filter * | Select-Object @{Label=‘computername’;Expression={$_.name}}

Yet, when I run the entire command the results did NOT look correct.

So I modified the command and added a select and a sort:

get-adcomputer -filter * | Select-Object @{Label=‘computername’;expression={$_.name}} | Get-Process |
Select-Object -Property MachineName, ProcessName, Id, VirtualMemorySize | Sort-Object -Property Id

Now the results shown below tell me I was correct and the results were not what I expected:

MachineName ProcessName Id VirtualMemorySize

LYNCDC6 Idle 0 0
LYNCDC6 Idle 0 0
LYNCDC6 Idle 0 0
LYNCDC6 Idle 0 0
LYNCDC6 System 4 3461120
LYNCDC6 System 4 3461120
LYNCDC6 System 4 3461120
LYNCDC6 System 4 3461120
LYNCDC6 smss 280 4644864
…

Is it possible that PowerShell 4 needs a different command than PowerShell 3?

get-host

Name : ConsoleHost
Version : 4.0
InstanceId : d0f58f22-df14-4b5c-b4f0-6b18a2c1f636
UI : System.Management.Automation.Internal.Host.InternalHostUserInterface
CurrentCulture : en-US
CurrentUICulture : en-US
PrivateData : Microsoft.PowerShell.ConsoleHost+ConsoleColorProxy
IsRunspacePushed : False
Runspace : System.Management.Automation.Runspaces.LocalRunspace

2

It looks like this might be a bug with Get-Process. I can reproduce it easily on the local computer (running PowerShell 5 with the latest preview):

$objects = @(
    [pscustomobject] @{ ComputerName = $env:COMPUTERNAME }
    [pscustomobject] @{ ComputerName = '.' }
)

Trace-Command ParameterBinding -PSHost -Expression {
    $procs = $objects | Get-Process
}

$procs | sort ID | Format-Table MachineName,ProcessName,ID

In the Trace-Command output, it looks like it’s binding both the ‘.’ and the full computer name strings to the ComputerName parameter properly, but for some reason only the first value in the list seems to be actually used when the cmdlet starts retrieving processes. I’ve poked around in the code a bit with ILSpy, and so far have not spotted where the problem is.

Edit: Scratch that, found the bug. Will pass the info on to Microsoft. Not sure if this is new to PS 4.0 or not; would have to set up a computer with PowerShell 3 to test.

In any case, not your fault; your code looks exactly like it should for ByPropertyName pipeline binding to work.

3

Bug report filed here, and I also emailed it on to the PS MVP mailing list: https://connect.microsoft.com/PowerShell/feedback/details/1164861