Output to file in powershell

Question

I want to output some information about devices to .txt file but something went wrong. Could someone tell me what the problem is?

   $devices=("wsu1","wsu2")
$file="C:\reports\file.txt"
 Invoke-Command -ComputerName $devices -ScriptBlock {
Get-WmiObject Win32_OperatingSystem |
Select PSComputerName, Caption, OSArchitecture, Version, BuildNumber | Out-File -FilePath $file
}
 & explorer.exe "C:\reports\"

I retrieve this message from the console:

Cannot bind argument to parameter 'FilePath' because it is null.
    + CategoryInfo          : InvalidData: (:) [Out-File], ParameterBindingValidationException
    + FullyQualifiedErrorId : ParameterArgumentValidationErrorNullNotAllowed,Microsoft.PowerShell.Commands.OutFileCommand

`$file` is not defined in the remote scope, it's defined in your local scope. If you want `Invoke-Command` to be able to see that variable defined locally you can use the `$using:` scope modifier: `-FilePath $using:file` — Santiago Squarzon, Aug 26 '22 at 16:38
Agreed^, or just place your `Out-File` outside of your `Invoke-Command`. — Abraham Zinala, Aug 26 '22 at 16:44
@SantiagoSquarzon I tried but I did something wrong could you please edit the code and show how it should be :) — Nick S, Aug 26 '22 at 17:38
What didn't "work"? Did you get an error? Did it just not output information? `Invoke-Command -ComputerName $devices -ScriptBlock { ... } | Out-File -FilePath $file`, what error did you receive when running this? — Abraham Zinala, Aug 26 '22 at 17:47
hmmmm, weird situation then. Santiagos recommedation is: `| Out-File -FilePath $using:file` If the intention is to place it on the remote computer, otherwise it would have to be outside the loop or referencing your system. — Abraham Zinala, Aug 26 '22 at 17:58
`$devices=("wsu1","wsu2") $file="C:\reports\file.txt" Invoke-Command -ComputerName $devices -ScriptBlock { Get-WmiObject Win32_OperatingSystem |
Select PSComputerName, Caption, OSArchitecture, Version, BuildNumber | Out-File -FilePath $using:file } & explorer.exe "C:\reports\" `Did I do that correctly? — Nick S, Aug 26 '22 at 18:09
@NickS Please [edit] your question to elaborate your [mcve] instead posting any code snippet in a comment. — JosefZ, Aug 26 '22 at 18:12
`Get-ADComputer -filter * -SearchBase "OU=HR,DC=SHELLPRO,DC=LOCAL" -Properties OperatingSystem | Sort Name | Export-Csv "c:\temp\version.csv ` I found another way to find what I need thank you for supporting ;) — Nick S, Aug 26 '22 at 18:59

score 1 · Accepted Answer · answered Aug 26 '22 at 20:18

Your immediate problem is that you tried to access a local variable, $file in a remotely executing script block, which cannot work, and defaults to $null, causing Out-File to report an error due to lack of an output file name.
- In any script block that runs in a different runspace (notably remotely, on other machines), you need to the $using: scope in order to use local variable values, such as $using:file in this case - see this answer for details.
However, the fact that you're executing & explorer.exe "C:\reports\" in an attempt to show the output file implies that you meant to write to a local file, which necessitates calling Out-File locally, outside the remote script block ({ ... }), in a separate pipeline segment.
- Note that this approach - piping to a single Out-File call - ensures that all output from the Invoke-Command call, across all computers targeted, is saved to the output file; see this answer for more information.

devices = "wsu1", "wsu2"
$file = "C:\reports\file.txt"

# Note the placement of the Out-File call.
Invoke-Command -ComputerName $devices -ScriptBlock {
    Get-WmiObject Win32_OperatingSystem |
      Select PSComputerName, Caption, OSArchitecture, Version, BuildNumber
  } |
  Out-File -FilePath $file

& explorer.exe "C:\reports\"

score -1 · Answer 2 · answered Aug 26 '22 at 19:06

-1

This might help... maybe... :)

# Prep some stuff
$Devices = @("wsu1","wsu2")
$File = "C:\reports\file.txt"
$Results = @()

# Work for each device
foreach ($Device in $Devices) {
    $Results += Invoke-Command -ComputerName $Device -ScriptBlock {
        Get-WmiObject Win32_OperatingSystem | Select-Object PSComputerName, Caption, OSArchitecture, Version, BuildNumber
    }
}

# Chuck it in a file
Set-Content -Value $Results -Path $File

answered Aug 26 '22 at 19:06

Neil

41
4

By switching to processing the devices (computers) _one by one, sequentially_, you're forgoing the benefits of calling _in parallel_. – mklement0 Aug 26 '22 at 20:04
Note that extending arrays in a loop with `+=` is inefficient, because a _new_ array must be created behind the scenes _in every iteration_, given that arrays are of fixed size; a much more efficient approach is to use a `foreach` loop as an _expression_ and let PowerShell itself collect the outputs in an array: `[array] $outputs = foreach (...) { ... }` - see [this answer](https://stackoverflow.com/a/60708579/45375). In case you need to create arrays manually, e.g. to create _multiple_ ones, use an efficiently extensible list type - see [here](https://stackoverflow.com/a/60029146/45375). – mklement0 Aug 26 '22 at 20:04

Output to file in powershell

2 Answers2