Multiple Reoccurring Processes

Question

I am testing a few domains and their ability to alert me when an abnormal event happens. I am using nmap to scan domains for open ports. The script below opens a new cmd window and runs nmap. I search for the process ID and checks to see if the process(cmd) is still running. Once the scan is over, it will run the nmap scan again.

function nmaptest {
    $prog1="cmd"
    $params1=@("/C";"nmap.exe -Pn -sX 192.168.1.0/24")
    Start-Process -Verb runas $prog1 $params1 #starts
}

while(1 -eq 1){
    nmaptest
    $processes = get-process $prog1 | out-string
    $sp = $processes.Split(' ',[System.StringSplitOptions]::RemoveEmptyEntries)
    $procid = $sp[22]
    echo $procid

    while(get-process -id $procid){ }
}

This works fine. What I need help with is doing this process 8 times in parallel. (if that is possible)

What is your version of PowerShell? – Piyush Sep 04 '15 at 13:03 — Piyush, Sep 04 '15 at 13:03

Deadly-Bagel · Accepted Answer · 2015-09-07T10:56:52.933

4

Well unless there's any specific reason you're launching CMD (such as needing to see the output) I'd recommend using jobs instead. They're easy to manage and test if they're still running.

$jobs = @()
$sx = '192.168.1.0/24', 'range2', 'etc'
For ($i = 0; $i -lt $sx.Length; $i++) { $jobs += Start-Job { nmap.exe -Pn -sX $sx[i] } }

while ($true) {
    For ($i = 0; $i -lt $sx.Length; $i++) { 
        if ($jobs[i].State -eq "Completed" {
            Write-Output ("Completed job for " + $sx[i])
            Receive-Job $jobs[i]
            $jobs[i] = Start-Job { nmap.exe -Pn -sX $sx[i] }
        } 
    }
    Start-Sleep -s 5
}

edited Sep 07 '15 at 10:56

answered Sep 04 '15 at 13:41

Deadly-Bagel

1,612
1
9
21

will this help run mulitple jobs in parallel? – Harry Singh Sep 04 '15 at 13:49
Jobs run asynchronously so yes – Deadly-Bagel Sep 04 '15 at 13:50
To clarify, the above script creates jobs and runs them in parallel, then repeatedly loops through them and restarts any that have finished. It runs as many jobs as you give it $sx parameters. Note I've just added a sleep in the loop so it's not running unnecessarily. – Deadly-Bagel Sep 04 '15 at 15:17
is there a way to see the output for each job to see if it is running properly? – Harry Singh Sep 04 '15 at 16:10
You can use `Receive-Job $jobs[i]` to get the output for that job. Updated answer to do this. – Deadly-Bagel Sep 07 '15 at 10:55

Multiple Reoccurring Processes

1 Answers1