run multiple .exe files at once python

Question

How do you run multiple .exe files at once in Python? I adapted code from another stack overflow question to make a LAN pinger. This pinger has to ping all devices within the subnet mask so in my case it has to run ping.exe 255 times. As a result, it takes a long time to run this. How can I run ping.exe multiple times at once?

The code I am currently using is as follows:

import subprocess
import os
with open(os.devnull, "wb") as limbo:
        print "SCANNING YOUR LAN..."
        for n in xrange(1, 256):
                ip="192.168.0.{0}".format(n)
                result=subprocess.Popen(["ping", "-n", "1", "-w", "200", ip],
                        stdout=limbo, stderr=limbo).wait()
                if result:
                        pass
                else:
                        print ip, "is active"

How do I make this program more efficient?

Answer 1

Don't put wait in your Popen call.

If you need them to run in parallel, but want to wait till they're all done before proceeding, do:

# Create a list of the running processes
running = [subprocess.Popen(...) for ip in ips]
# Wait /after/ all process have launched. 
[process.wait() for process in running]
# Rest of code here.

Of course you have to reformulate things a little to make the ips list, etc.

Answer 2

Well if you had a file called "ipaddress.txt" with all the IPs you could do something like I imagine:

    f = open('ipaddress.txt')
    lines = f.readlines()
    f.close()
    for line in lines:
        subprocess.Popen(["ping", "-a", "-n", "l"]

Even if that code doesn't work it still should be the concept. You need to ping 192.168.0.1/255, and have the active ips displayed back to you.