Stop a scan midway by pressing a key

Question

Stop a scan midway by pressing a key

Gaetan Meister 21

I'm adding a scan in my script to check for available IPs in 2 subnets. I would like to be able to stop the scan midway. How would I achieve that so that we don't wait until the end of the scan ? CTRL-C will skip then end of the bigger script

# Subnet selection
function Show-Menu
    {param ( [string]$Title = 'subnet selection' )
     Write-Host "================ $Title ================"
     Write-Host "1: 192.168.128.0/24"
     Write-Host "2: 192.168.129.0/24"
     }
do
{Show-Menu
$input = Read-Host "Which subnet will the VM be on"
switch ($input)
     {
           '1' {$subnet="128_subnet"; $GW="192.168.128.1"}            
           '2' {$subnet="129_subnet"; $GW="192.168.129.1"} 
     }
 } until ($input)

2 answers

Your answer

Answer 1

Apologies. wrong script

 # Subnet selection
 function Show-Menu
     {param ( [string]$Title = 'subnet selection' )
      Write-Host "================ $Title ================"
      Write-Host "1: 192.168.128.0/24"
      Write-Host "2: 192.168.129.0/24"
      }
 do
 {Show-Menu
 $input = Read-Host "Which subnet will the VM be on"
 switch ($input)
      {
   '1' {2..250|ForEach { if (!((Test-Connection 192.168.128.$_ -count 1 -Quiet) -and (resolve-dnsname -ea 0 192.168.128.$_ ))) {write-Output "IP Address Available 192.168.128.$_ and no DNS entries"}}}
   '2' {2..250|ForEach { if (!((Test-Connection 192.168.129.$_ -count 1 -Quiet) -and (resolve-dnsname -ea 0 192.168.129.$_ ))) {write-Output "IP Address Available 192.168.129.$_ and no DNS entries"}}}
      }
  } until ($input)

Answer 2

Rich Matheisen 47,901

You'll need to deal $host and poll for a keypress:

stop-powershell-with-keypress

Gaetan Meister 21

Right but how do I insert it in my script. I tried the statement below and pressing q didn't do anything

 while($true) {
    2..250|ForEach { if (!((Test-Connection 192.168.127.$_ -count 1 -Quiet) -and (resolve-dnsname -ea 0 192.168.127.$_ ))) {write-Output "IP Address Available 192.168.127.$_ and no DNS entries"}}

    if($Host.UI.RawUI.KeyAvailable -and ("q" -eq $Host.UI.RawUI.ReadKey("IncludeKeyup,NoEcho").Character)) { Write-Host "Exiting now, don't try to stop me...." -BackgroundColor DarkRed
        break;
    }
}

Rich Matheisen 47,901 Reputation points

2021-12-01T21:10:17.47+00:00

Using a "ForEach {...}" to control the loop won't work (because the loop is managed by a stream). Using "ForEach ($octet in 2..250)" as the loop control would allow you to use "Break" to exit the loop.

You'll have to include the "if ($Host.UI.RawUI......" test inside the ForEach code block.

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Stop a scan midway by pressing a key

2 answers

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