Skip to content

Bash: Script to find active computers in a subnet using ping

by mat on January 27th, 2010

The following is a simple bash script that will scan each ip address in a give subnet and report if they are alive (or accepting ping requests). The code creates processes for each ping so that it completes quickly rather than scanning each ip address sequentially.

Create a text file called “pinger.sh” and paste the following into it:

#!/bin/sh

: ${1?"Usage: $0 ip subnet to scan. eg '192.168.1.'"}

subnet=$1
for addr in `seq 0 1 255 `; do
#   ( echo $subnet$addr)
( ping -c 3 -t 5 $subnet$addr > /dev/null && echo $subnet$addr is Alive ) &
done 

Save and close, then it can be called from the command line like so:

sh pinger.sh 192.168.1.

This will scan from 192.168.1.0 to 192.168.1.255 and will return something like the following:

192.168.1.1 is Alive
192.168.1.105 is Alive
192.168.1.112 is Alive
192.168.1.149 is Alive
4 Comments
  1. Your example will only scan 192.168.1.1 and above. You need to change your sequence if you want .0 in there.

    for addr in ‘seq 0 1 255 ‘; do

  2. Ah good spot!

  3. anoop permalink

    just give while loop construction for pinging any subnet

  4. Use arping commad. Some machines may have firewall blocking ICMP-echo, but they will respond go arping.
    arping will also not work acros networks i.e. routers will block it.

Leave a Reply

Note: I am currently writing my thesis so probably wont have time to reply to your comment
Note: XHTML is allowed. Your email address will never be published.

Subscribe to this comment feed via RSS