Retrieving Computer Names That Produced an Error From Invoke-Command - powershell

Question

I'm working on speeding the execution of a script and long story short, the core of it would look similar to this (minus Measure-Command):
$devices = Get-Content "list.txt"
Measure-Command{
try{
$Result = Invoke-Command -ComputerName $devices -ScriptBlock {
Get-LocalUser | Select-Object -Property #{N="Computer"; E={$env:COMPUTERNAME}},
Name, Enabled, PasswordChangeableDate, PasswordExpires, UserMayChangePassword,
PasswordRequired, PasswordLastSet, LastLogon,
#{n="Groups"; E={
$user = $_
Get-LocalGroup | Where-Object { $user.SID -in ($_ | Get-LocalGroupMember | Select-Object -ExpandProperty "SID") } | Select-Object -ExpandProperty "Name"
}}
} 2>> "errors.txt"
}catch{
Write-Host "Uh oh..." -ForegroundColor Red
Write-Host $Error[0]
}
}
What I'm trying to figure out is, in the case of an error on one of the devices, I want to store that device name in a separate file. In the past I was doing all of this process via a foreach loop with try/catch, which made this part very easy. I'm looking to avoid that with this solution.
Right now, I'm using 2>> "errors.txt" courtesy of this post, but this records the full error, which I don't want. Example:
[EXAMPLE DEVICE] Connecting to remote server EXAMPLE DEVICE failed with the following error message : WinRM cannot process the
request. The following error occurred while using Kerberos authentication: Cannot find the computer EXAMPLE DEVICE. Verify that
the computer exists on the network and that the name provided is spelled correctly. For more information, see the
about_Remote_Troubleshooting Help topic.
+ CategoryInfo : OpenError: (EXAMPLE DEVICE:String) [], PSRemotingTransportException
+ FullyQualifiedErrorId : NetworkPathNotFound,PSSessionStateBroken
I'd like the only record the name of the device (in this case "EXAMPLE DEVICE") in the file. Is there a way to do this?

Answer 1

One way to handle is to set -ErrorActions SilentlyContinue -ErrorVariable Errs.
This enables the program to flow normally without bleeding red errors all over the screen. Then you can look at the error records stored in $Errs to report on which machines had issues. In your case $Errs.TagrgetObject.
Demo might be something like
Invoke-Command -ComputerName $Computers -ScriptBlock { "Whatever..." } -ErrorAction SilentlyContinue -ErrorVariable Errs
# PostOp Check which machines had errors:
$Errs.TargetObject
This should return:
MrBogus
MrsBogus
Of course, if you want to format that more robustly you can do any arbitrary processing on the error records.