Unable to compare ping times on fly

Question

I tried the following command unsuccessfully

sdiff <(ping www.nato.int) <(ping www.reuters.com)

Is there any way to have a real-t

Answer 1

How about:

watch 'ping -c 4 www.google.com; echo; ping -c 4 www.yahoo.com'

Gives result such as this:

Every 2.0s: ping -c 4 www.google.com; echo; ping -c 4 www.yahoo.com                                                                          Tue Apr  7 13:57:47 2009

PING www.l.google.com (74.125.39.105) 56(84) bytes of data.
64 bytes from fx-in-f105.google.com (74.125.39.105): icmp_seq=1 ttl=248 time=8.06 ms
64 bytes from fx-in-f105.google.com (74.125.39.105): icmp_seq=2 ttl=248 time=8.47 ms
64 bytes from fx-in-f105.google.com (74.125.39.105): icmp_seq=3 ttl=248 time=8.37 ms
64 bytes from fx-in-f105.google.com (74.125.39.105): icmp_seq=4 ttl=248 time=8.19 ms

--- www.l.google.com ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 2999ms
rtt min/avg/max/mdev = 8.061/8.276/8.478/0.196 ms

PING www-real.wa1.b.yahoo.com (87.248.113.14) 56(84) bytes of data.
64 bytes from f1.us.www.vip.ird.yahoo.com (87.248.113.14): icmp_seq=1 ttl=56 time=43.3 ms
64 bytes from f1.us.www.vip.ird.yahoo.com (87.248.113.14): icmp_seq=2 ttl=56 time=44.3 ms
64 bytes from f1.us.www.vip.ird.yahoo.com (87.248.113.14): icmp_seq=3 ttl=56 time=42.4 ms
64 bytes from f1.us.www.vip.ird.yahoo.com (87.248.113.14): icmp_seq=4 ttl=56 time=43.0 ms

--- www-real.wa1.b.yahoo.com ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 2999ms
rtt min/avg/max/mdev = 42.422/43.277/44.301/0.728 ms

Do you need to subtract the ping times? Does it have to be side by side (a bit annoying)? What's your ideal output format?