Count Events by ICMP
This DTrace one-liner count events by ICMP:
# dtrace -n 'icmp:::send,icmp:::receive { @i[icmp_type_string[args[4]->icmp_type]] = count(); }'
dtrace: description 'icmp:::send,icmp:::receive ' matched 25 probes
^C
Echo reply 7
Echo request 7