Fastest way to ping a network range and return responsive hosts?

Constraints:

1. Speed matters.
2. I am allowed to ping once.

I'm debating whether to use Python or shellscripting. Is there a method faster than bash?

Here is the current code,

for ip in $(seq int1 int2); do
    ping -c 1 xxx.xxx.xxx.$ip | grep "bytes from" &
done

Anything faster than this?

You should use NMAP:

nmap -T5 -sP 192.168.0.0-255

The following (evil) code runs more than TWICE as fast as the nmap method

for i in {1..254} ;do (ping 192.168.1.$i -c 1 -w 5  >/dev/null && echo "192.168.1.$i" &) ;done

takes around 10 seconds, where the standard nmap

nmap -sP 192.168.1.1-254

takes 25 seconds...

Try this for a unique list.

ping -c 5 -b 10.10.0.255 | grep 'bytes from' | awk '{ print $4 }' | sort | uniq

another method (fetches live hosts):

fping -ag 192.168.1.0/24

Try both of these commands and see for yourself why arp is faster:

PING:

for ip in $(seq 1 254); do ping -c 1 10.185.0.$ip > /dev/null; [ $? -eq 0 ] && echo "10.185.0.$ip UP" || : ; done

ARP:

for ip in $(seq 1 254); do arp -n 10.185.0.$ip | grep Address; [ $? -eq 0 ] && echo "10.185.0.$ip UP" || : ; done

This is python code for the ping in range of the 192.168.0.0-192.168.0.100. You can change for loop as you comfort.

# -*- coding: utf-8 -*-
import socket
import os
import sys

up_ip =[] #list to store the ip-addresses of server online
for x in range(100):  #here range is 0-100. You can change the range according to your comfort

	server_ip = '192.168.0.'+ str(x)
	print "Trying ,server_ip,... \n"

	rep = os.system('ping -c 1 ' + server_ip)

	if rep == 0:
		up_ip.append(server_ip)
		print '******************* Server Is Up **************** \n'
	else:
		print 'server is down \n'

print up_ip

This script runs on Git Bash (MINGW64) on Windows and return a messages depending of the ping result.

#!/bin/bash
#$1 should be something like "19.62.55"

if [ -z "$1" ]
  then
    echo "No identify of the network supplied, i.e. 19.62.55"
else
	ipAddress=$1
	
	for i in {1..256} ;do 
	(
		{
		ping -w 5 $ipAddress.$i ; 
		result=$(echo $?);
		} &> /dev/null
		

		if [ $result = 0 ]; then
			echo Successful Ping From : $ipAddress.$i
		else
			echo Failed Ping From : $ipAddress.$i
		fi &);
	done

fi

BSD's

for i in $(seq 1 254); do (ping -c1 -W5 192.168.1.$i >/dev/null && echo "192.168.1.$i" &) ;done

If time matters (and I know the feeling):

for i in {1..254}; do
echo -n -e "$i      \r" 	
timeout --preserve-status .2  ping -c1 -q 10.0.0.$i  &> /dev/null
[ $? -eq 0 ]&&echo 10.0.0.$i is happy to serve to his master!
done # as I am

The command:

timeout --preserve-status .2  ping -c1 -q 10.0.0.107 &> /dev/null  ;echo $? 

returns 143 with non-existing PC and 0 with existing PC and waits for the answer just and only for .2 second because TIME MATTERS! And therefore I have to look for my lost keys now.