How do I turn this simple command into something that loops from a list of remote systems? - powershell-2.0

Question

I received a request to run this on each of my systems which pulls a list of installed applications and outputs it into a text file. I then have to combine all of these things into something more readable which will take a while. I am learning Powershell and want to make this be executed from one system, pull from a list of servers in a text file and run this query from one place against all of the systems:
Get-ItemProperty HKLM:\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\* | Select-Object DisplayName, DisplayVersion, Publisher, InstallDate | Format-Table –AutoSize > "$Env:userprofile\desktop\Installed Programs for $env:computername.txt"
I've started working on it but am thinking I am missing something to get this to work. I am currently piping this to a string to then output to a csv (I am open to suggestions). This is what I have so far.
# Computer running this script
$WhoAmI = $env:ComputerName
$ServerList = get-content -path "C:\scripts\ServerList.txt"
$Path = "C:\scripts\results"
foreach ($server in $ServerList)
{
$InstalledApps = Invoke-Command -ComputerName $server {Get-ItemProperty HKLM:\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\* }
$Results += $InstalledApps |
Select-Object DisplayName, DisplayVersion, Publisher, InstallDate |
Out-String
}
Write-Host $InstallApps
# $InstallApps | export-csv "$Path\InstalledFiles.csv"
I currently am testing the functionality of the loop by just trying to get it to write to the screen. I only get a blank response.

Answer 1

You weren't getting output because you used the (undefined) variable $InstallApps instead of the variable $results.
With that said, I wouldn't recommend doing string concatenation in a loop. Something like this would be a more elegant approach:
Get-Content -Path 'C:\scripts\ServerList.txt' | ForEach-Object {
$server = $_
Invoke-Command -ComputerName $server -ScriptBlock {
Get-ItemProperty HKLM:\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\*
} | Select-Object #{n='Server';e={$server}}, DisplayName, DisplayVersion,
Publisher, InstallDate
} | Export-Csv 'C:\scripts\results\InstalledPrograms.csv' -NoType

Answer 2

I kind of figured it out. Rested eyes on a fresh day. Some mistakes in what I am writing out, etc. I am open to improvements if anyone has anything to contribute.
EDIT: I got it working mostly with the following but the output is messy. Open to suggestions.
# Computer running this script
$ServerList = get-content -path "C:\scripts\ServerList.txt"
$Path = "C:\scripts\results"
foreach ($server in $ServerList)
{
$Results += "Results for $server"
$InstalledApps = Invoke-Command -ComputerName $server -ScriptBlock {Get-ItemProperty HKLM:\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\* }
$Results += $InstalledApps |
Select DisplayName, DisplayVersion, Publisher, InstallDate |
Out-String
}
# Write-Host $Results
$Results | out-file -filepath "$Path\InstalledPrograms.txt" -width 200