Normal ping operation is continuous.

ping 8.8.8.8

To get intermittent statistics, the SIGQUIT signal can be sent to the ping command.

Example output:

64 bytes from 8.8.8.8: icmp_seq=185 ttl=116 time=20.8 ms
64 bytes from 8.8.8.8: icmp_seq=186 ttl=116 time=22.1 ms
186/186 packets, 0% loss, min/avg/ewma/max = 20.775/24.063/23.094/37.955 ms
64 bytes from 8.8.8.8: icmp_seq=187 ttl=116 time=21.3 ms
64 bytes from 8.8.8.8: icmp_seq=188 ttl=116 time=22.7 ms
64 bytes from 8.8.8.8: icmp_seq=189 ttl=116 time=28.3 ms

Key combination while running:
CTRL+\ or CTRL+| or CTRL+4;

Send to one or more known pids

kill -SIGQUIT <pid> [...]

Send to all running

ps -o pid= -C ping | xargs -r kill -SIGQUIT

Periodically send to all running

while sleep 20; do ps -o pid= -C ping | xargs -r kill -SIGQUIT; done

As a background job

while sleep 20; do ps -o pid= -C ping | xargs -r kill -SIGQUIT; done &