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...