Loop Foreach only repeat offline computers - powershell

Question

Not sure where I am going wrong I want to skip the computers which are coming back online but it keeps checking both online and online computers.
1st update is fine that its coming online and it should skip and only ping the offline one's a screenhot of output
g-10 Is coming online...Skipping to offline one's
192.168.0.1 Is coming online...Skipping to offline one's
Testing to see if Hero is coming online...
Hero is Offline. Pausing for 2 seconds. Remaining attempts: 1
Testing to see if zero is coming online...
zero is Offline. Pausing for 2 seconds. Remaining attempts: 1
Its fine upto here but online computers again repeated...
g-10 Is coming online...Skipping to offline one's
192.168.0.1 Is coming online...Skipping to offline one's
Testing to see if Hero is coming online...
Hero is Offline.
here is my code
$Comps = GC c:\restarted.txt
[int]$SleepTimer = "1" #minutes to attempt after
[int]$SleepSeconds = $SleepTimer * 2
[int]$Attempts = "2"
[int]$AttemptsCounter = 0
Do
{
$AttemptsCounter++
$RemainingAttempts = ([int]$Attempts - [int]$AttemptsCounter)
Foreach($comp in $comps){
$Online = Test-Connection -ComputerName $Comp -Quiet
IF($online -eq "True"){
Write-Host "$comp" -BackgroundColor Green -NoNewline
Write-Host " Is coming online...Skipping to offline one's"
}
elseIf ($Online -NE "True")
{
Write-Host "Testing to see if $Comp is coming online..."
Write-Host "$comp" -BackgroundColor Red -NoNewline
Write-Host " is Offline" -BackgroundColor Red -ForegroundColor Black -NoNewline
If ($AttemptsCounter -eq $Attempts) {
Write-Host "."
}
Else {
Write-Host ". Pausing for $SleepSeconds seconds. Remaining attempts: $RemainingAttempts"
}
}
}
#Check the number of attempts, break out if reached.
If ($AttemptsCounter -eq $Attempts) {break}
#Delay
Start-Sleep -s ($SleepTimer * 60)
}
While ($Online -NE "True")
If ($Online -NE "True") {
Write-Host "Maximum number of attempts reached"
}
Else {
Write-Host
Write-Host "Computer $Comp is " -NoNewline
Write-Host "ONLINE" -BackgroundColor Green
}

Answer 1

try the following code.
It basically does the following for each line in c:\restarted.txt:
tests if the computer is online (Note: I added -Count 1)
if it is online: prints some green text and break
if it is offline: print red text, wait and decrements the $RemainingAttempts variable and redo until $RemainingAttempts is 0 or the computer is online
it the $RemainingAttempts variable is 0 print out some more text
$ComputerNameArray = Get-Content -Path c:\restarted.txt
[int]$SleepTimer = "1" #minutes to attempt after
[int]$Attempts = "2"
$DefaultBackgroundColor = (Get-Host).ui.rawui.BackgroundColor
foreach($ComputerName in $ComputerNameArray) {
$AttemptsCounter = 0
$RemainingAttempts = $Attempts - $AttemptsCounter
Write-Host "Testing to see if ""$ComputerName"" is coming online..." -BackgroundColor $DefaultBackgroundColor
while($RemainingAttempts -gt 0) {
if(Test-Connection -ComputerName $ComputerName -Quiet -Count 1) {
Write-Host """$ComputerName""" -BackgroundColor Green -NoNewline
Write-Host " Is coming online...Skipping to offline one's"
break
} else {
Write-Host """$ComputerName""" -BackgroundColor Red -NoNewline
Write-Host " is Offline" -BackgroundColor Red -ForegroundColor Black -NoNewline
Write-Host ". Pausing for $SleepTimer minutes. Remaining attempts: $($RemainingAttempts - 1)"
Start-Sleep -Seconds ($SleepTimer * 60)
$RemainingAttempts--
}
}
if($RemainingAttempts -eq 0) {
Write-Host "Maximum number of attempts reached" -BackgroundColor $DefaultBackgroundColor
}
}
hope this helps!
Let me know if you have any question concerning the code.
KR
Guenther

Answer 2

Test-Connection returns an array of objects or a $null depending if the ip or hostname is live.
so its enough if you do this:
IF($online){
// if its alive
}
else
{
// if its not responding
}
another thing to point out is you dont have to
if(condition) {
}
elseif(condition) {
}
if you are testing "bool question-answer" you don't need the elseif. In your case, if you are checking the state of computer then you can't have more answers than 2 (yes/no). So the elseif is in this case redundant.
if(condition) {
// if the condition is true
}
else {
// if the condition is not true. you can't have the third option
}
Also your if condition If ($Online -NE "True") is checking if the variable $Online is not equal the exact string "true" or "True" since -ne is case insensitive condition operator.
You should check if the variable holds anything or holds $Null

Answer 3

While I know Guenther Schmitz has already got the green check, I wanted to follow up with some additional details and pointers.
Test-Connection with the -Quiet switch returns a [Boolean] type. This is a simple true/false. I like to be extra careful with comparing string values to Boolean values because you can get some odd results depending on how you frame your tests. For example:
'false' -eq $true
$true -eq 'false'
Top one equals false, bottom one equals true because PowerShell is converting the second object into the same type as the first, and a non-empty string is true. So my strong recommendation is to stick to typed comparisons. So the first code change I'd start with is:
if ($Online -eq $true) {
As #pandemic already mentioned, you're doing a simple comparison, so no need for elseif, just else.
The second issue you have is that there is nothing removing computers from your testing list. The way your code is written, if the last computer in your testing list is "down" then it'd go through all the computers again. If the last computer in the list is "up" then it'd quit the do|while loop, irregardless of how many computers you are testing and how many are down. You can verify this with a simple test of putting 1 known hosts, and 1 fake host in the test file. If the known good host is first, it'll keep looping until $AttemptsCounter reaches the maximum allowed. If you flip the list around, it'll bail out immediately after testing the known good host.
Your initial code looped through all the computers once then went back and started again. In Guenther's example, they loop one computer at a time, and check until it comes up, or bail out after exceeding the test count. I think Guenther's example was probably what you were after, but if you wanted to make it cycle through all the computers, and then test only those that had failed, I'd write something like this:
$comps = Get-Content -path 'c:\restarted.txt'
[int]$SleepTimer = 1
[int]$Attempts = 2
[int]$AttemptsCounter = 0
do {
Write-Host "Testing Network, attempt $($AttemptsCount + 1)"
$newComps = #()
foreach($comp in $comps) {
$online = Test-Connection -Quiet -Count 1 -ComputerName $comp
if ($online) {
Write-Host "$comp" -BackgroundColor Green -NoNewline
Write-Host " Is coming online...Skipping to offline one's"
} else {
$newComps += $comp
Write-Host "$comp" -BackgroundColor Red -NoNewline
Write-Host " is Offline" -BackgroundColor Red -ForegroundColor Black
}
}
$comps = $newComps
$AttemptsCounter++
Start-Sleep -Seconds ($SleepTimer * 60)
}
while (($comps.count -gt 0) -and ($AttemptsCounter -lt $Attempts))
if ($comps.Count -gt 0) {
Write-Host "Exceeded Attempts Counter" -BackgroundColor Red
}
In this code, it is taking the list of computers, and when it fails on a computer, it stuffs it into a temporary list for reuse.