PowerShell test-connection, if service exists using get-service - powershell

Question

Basically I want to check and see if the computers in the text file are online. If they aren't online then write-host "$computer is down". If the $computer is online then check to see if this service exists, if it exists then write-host "$computer installed, if not then write-host "$computer not installed". The Test-connection seems to work but if the computer is online they all return write-host "$computer installed" even though I have a test machine that I know doesn't have this service running.
function Get-RunService {
$service = get-service -name ABCService
Get-Content "C:\powershell\computers.txt" |
foreach {if (-not (Test-Connection -comp $_ -quiet))
{
Write-host "$_ is down" -ForegroundColor Red
}
if ($service )
{
write-host "$_ Installed"
}
else {
Write-host "$_ Not Installed"
}
}
}
get-RunService

Answer 1

Have a look at this cleaned up version of your code.
function Get-RunService {
Get-Content "C:\powershell\computers.txt" |
foreach {
if (-not (Test-Connection -comp $_ -quiet)){
Write-host "$_ is down" -ForegroundColor Red
} Else {
$service = get-service -name ABCService -ComputerName $_ -ErrorAction SilentlyContinue
if ($service ){
write-host "$_ Installed"
} else {
Write-host "$_ Not Installed"
}
}
}
}
get-RunService
I tried to clean up how the brackets were working. Your check if the host was alive did not have an Else to separate the case off the server being contactable or not. Side note is that ping could fail but the host could still be alive and that all depends on your environment but be aware of the possibility. Also moved the $service line into the foreach adding the -ComputerName $_
Currently you have no margin for error with this. That function is possible to not exist and you should account for that. Best advice would be to look into -ErrorAction of Get-Service and possibly a Try/Catch block.

Answer 2

It's been a while, but I think this version is a bit more clear. Why check for it to be offline instead of only performing the actions if the computer is online.
function Get-RunService {
Get-Content "C:\powershell\computers.txt" |
foreach
{
if (Test-Connection -comp $_ -quiet)
{
$service = get-service -name ABCService -ComputerName $_ -ErrorAction SilentlyContinue
if ($service ) { Write-Host "$_ Installed" }
else { Write-Host "$_ Not Installed" }
}
else
{ Write-Host "$_ is offline!" -ForegroundColor Red }
}
}