Powershell: Combining Variables in Output

Question

I'm trying to put together a very simple code that outputs the server name, the last reboot date, and then the difference in hours and days. I've tried several iterations of Write-Host, but I can't seem to get the output I expect. The output should be something like this:
ServerName | Reboot Date | Time Running (Day, Hours)

Here is the code:

begin {}
process {
  foreach($server in (gc d:\win_IP.txt)){
    if(Test-Connection -ComputerName $server -Count 1 -ea 0) {
      $strFQDN = [System.Net.Dns]::GetHostbyAddress($server) | Select-Object HostName -ErrorAction "SilentlyContinue"
      $wmi = Get-WmiObject -Class Win32_OperatingSystem -Computer $server 
      $strDate = $wmi.ConvertToDateTime($wmi.LastBootUpTime)
      $strDiff = [DateTime]::Now - $wmi.ConvertToDateTime($wmi.LastBootUpTime) | Format-Table Days, Hours
    } else {
      Write-Verbose "$server is offline"
    }            
  }
}            

end {}

If someone could explain just how combining variables works, as well as how to format the output, I'd really appreciate it.

Thanks in advance.

What output are you getting? You should use the -Quiet parameter if you are using Test-Connection in an if statement. — Benjamin Hubbard
– Benjamin Hubbard, Commented Oct 7, 2014 at 23:05

Benjamin Hubbard · Accepted Answer · 2014-10-07 23:23:01Z

6

Try this:

foreach ($server in (Get-Content "d:\win_IP.txt")){
    if (Test-Connection -ComputerName $server -Count 1 -Quiet) {
        $strFQDN = [System.Net.Dns]::GetHostbyAddress($server)
        $wmi = Get-WmiObject -Class Win32_OperatingSystem -Computer $server 
        $strDate = $wmi.ConvertToDateTime($wmi.LastBootUpTime)
        $strDiff = [DateTime]::Now - $strDate

        [PSCustomObject]@{
            "ServerName" = $strFQDN.HostName
            "Reboot Date" = $strDate
            "Time Running" = "$($strDiff.Days) days, $($strDiff.Hours) hours"
        }

    } else {
        Write-Verbose "$server is offline"
    }            
}

What I did was store each field in a single object, then just outputted that object without formatting it. Typically not a good idea to format objects because then they are converted to strings and cannot be used for anything other than outputting to host/file.

answered Oct 7, 2014 at 23:23

Benjamin Hubbard

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1 Comment

user2521736 Over a year ago

This works perfectly, Entbark! Thank you so much for explaining just how it works as well; I'll be sure to get a better understanding of Objects for my next script task!

Sam Porch · Accepted Answer · 2014-10-08 07:33:29Z

Entbark's answer is probably what you're after—if you're using PowerShell 3.0. The HashTable-to-Object notation doesn't work in PowerShell 2.0.

Instead, see below for more options. The main point, though, is that you combine variables by creating a new object and adding the variables as properties to that object.

(Also, I wasn't aware of Test-Connection, is it just me or is it super slow?)

Intro:

ForEach ($server in (gc 'D:\win_IP.txt')) {
    $Pinger = New-Object System.Net.NetworkInformation.Ping
    if( $Pinger.Send( $server, 500 ).Status -eq "Success" ) {
        $strFQDN = [System.Net.Dns]::GetHostbyAddress($server) |
            Select HostName -ErrorAction "SilentlyContinue"
        $wmi = Get-WmiObject -Class Win32_OperatingSystem -Computer $server 
        $strDate = $wmi.ConvertToDateTime($wmi.LastBootUpTime)
        $strDiff = [DateTime]::Now - $strDate

Combine Variables Option 1:

        $OutObject = New-Object PSObject
        $OutObject | Add-Member NoteProperty 'FQDN' ($strFQDN)
        $OutObject | Add-Member NoteProperty 'Date' ($strDate)
        $OutObject | Add-Member NoteProperty 'Diff' ($strDiff)

        # 1 A:
        Write-Output $OutObject

        # 1 B:
        $OutObject | Format-Table

Combine Variables Option 2:

        Write-Output ( (New-Object PSObject) |
            Add-Member NoteProperty 'FQDN' ($strFQDN) -PassThru |
            Add-Member NoteProperty 'Date' ($strDate) -PassThru |
            Add-Member NoteProperty 'Diff' ($strDiff) -PassThru )

Combine Variables Option 2B:

        ( (New-Object PSObject) |
            Add-Member NoteProperty 'FQDN' ($strFQDN) -PassThru |
            Add-Member NoteProperty 'Date' ($strDate) -PassThru |
            Add-Member NoteProperty 'Diff' ($strDiff) -PassThru ) | Format-Table

Outro:

    } else {
        Write-Verbose "$server is offline"
    }
}

Sam, thanks a lot for your help - it always seems there's a dozen different ways to get the same result when coding. I'm sure I'm going to use your examples in my next script. Thanks for taking the time to explain and demonstrate!

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