Empty variable after Invoke-Command - powershell

Question

I want to get the most errors of a list of servers and save it in the variable $AllErrors.
But the variable is empty if I want to print it out.
Is there a way to pass the variable out of the Invoke-Command?
This is my code:
Get-Content -Path C:\Users\$env:USERNAME\Desktop\Server.txt |
ForEach-Object{
Invoke-Command -ComputerName $_ -ScriptBlock{
$Date = (Get-Date).AddHours(-12)
$Events = Get-WinEvent -FilterHashtable #{LogName = 'System'; StartTime = $Date; Level = 2}
$Errors = $Events | Group-Object -Property ID -NoElement | Sort-Object -Property Count -Descending |
Select-Object -Property Name -First 1
}
}
$Errors | Out-File -FilePath C:\Users\$env:USERNAME\Desktop\AllErrors.txt

Answer 1

No, it's not possible, however you can assign the output of Invoke-Command to a variable. $Errors seems to be the only output of your Invoke-Command, so this should work. But looking at your code you will only get Errors for the last computer as you are constantly overwriting the $Errors variable in cycle. You should either declare $Errors outside of cycle, and append errors to it, or append to file after each cycle:
Get-Content -Path C:\Users\$env:USERNAME\Desktop\Server.txt |
ForEach-Object{
$Errors = Invoke-Command -ComputerName $_ -ScriptBlock{
$Date = (Get-Date).AddHours(-12)
$Events = Get-WinEvent -FilterHashtable #{LogName = 'System'; StartTime = $Date; Level = 2}
$Events | Group-Object -Property ID -NoElement | Sort-Object -Property Count -Descending |
Select-Object -Property Name -First 1
}
$Errors | Out-File -FilePath C:\Users\$env:USERNAME\Desktop\AllErrors.txt -Append
}