Linux下的ping命令
-i可设置ping的时间间隔。以下每隔6秒ping一次Google：
-i可设置ping的时间间隔。以下每隔6秒ping一次Google：
$ ping google.com -i6
如果不是管理员且把-i设置为低于0.2秒的时间间隔就会被系统禁止，被认为是泛洪攻击（Flood）了：
$ ping 127.0.0.1 -i 0.1PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.ping: cannot flood; minimal interval, allowed for user, is 200ms
当然你可以切换到root去这么干：
# ping 127.0.0.1 -i 0.1PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.008 ms
并且可以公开声明我就是要这么干（执行泛洪攻击）：
# ping 127.0.0.1 -fPING 127.0.0.1 (127.0.0.1) 56(84) bytes of data....^C--- 127.0.0.1 ping statistics ---88347 packets transmitted, 87885 received, 0% packet loss, time 20694msrtt min/avg/max/mdev = 0.000/0.004/1.975/0.040 ms, pipe 2, ipg/ewma 0.234/0.006 ms
有3种方法ping本地（Localhost）：
$ ping 0$ ping localhost$ ping 127.0.0.1
-c指定ping的次数（在Linux下默认是一直ping下去不停止；Windows默认ping 5次）：
$ ping google.com -n -c3PING google.com (173.194.72.138) 56(84) bytes of data.64 bytes from 173.194.72.138: icmp_seq=1 ttl=37 time=73.5 ms64 bytes from 173.194.72.138: icmp_seq=2 ttl=37 time=76.6 ms64 bytes from 173.194.72.138: icmp_seq=3 ttl=37 time=79.6 ms--- google.com ping statistics ---3 packets transmitted, 3 received, 0% packet loss, time 2001msrtt min/avg/max/mdev = 73.550/76.624/79.659/2.504 ms
-w指定ping的时间，超时后ping就会退出（默认1秒ping一次，设置3秒超时的话通常就发3个ping报文）。
$ ping baidu.com -w3PING baidu.com (123.125.114.144) 56(84) bytes of data.64 bytes from 123.125.114.144: icmp_seq=1 ttl=46 time=19.2 ms64 bytes from 123.125.114.144: icmp_seq=2 ttl=46 time=18.0 ms64 bytes from 123.125.114.144: icmp_seq=3 ttl=46 time=88.8 ms--- baidu.com ping statistics ---3 packets transmitted, 3 received, 0% packet loss, time 2001msrtt min/avg/max/mdev = 18.090/42.070/88.868/33.094 ms
-q抑制ping的输出，这样就可以获得一份统计数据而不必关系每个ping包的结果了：
$ ping google.com -c100 -i0.2 -qPING google.com (74.125.31.138) 56(84) bytes of data.--- google.com ping statistics ---100 packets transmitted, 99 received, 1% packet loss, time 19855msrtt min/avg/max/mdev = 44.869/90.113/165.976/17.336 ms
也可以通过输入Ctrl+|随时获取一份统计信息（发送了一个SIGQUIT信号）：
$ ping baidu.com PING baidu.com (220.181.111.86) 56(84) bytes of data.64 bytes from 220.181.111.86: icmp_seq=1 ttl=53 time=2.78 ms...64 bytes from 220.181.111.86: icmp_seq=5 ttl=53 time=5.86 ms5/5 packets, 0% loss, min/avg/ewma/max = 2.789/3.956/3.431/5.866 ms64 bytes from 220.181.111.86: icmp_seq=6 ttl=53 time=5.59 ms...64 bytes from 220.181.111.86: icmp_seq=10 ttl=53 time=8.90 ms11/10 packets, 9% loss, min/avg/ewma/max = 2.789/4.823/4.638/8.903 ms64 bytes from 220.181.111.86: icmp_seq=11 ttl=53 time=21.8 ms...
-s设置每个ping报文（其实是ICMP报文）的大小，默认是56：
$ ping google.com -s1024 -n # ICMP回复报文被截断了PING google.com (173.194.72.100) 1024(1052) bytes of data.72 bytes from 173.194.72.100: icmp_seq=1 ttl=34 (truncated)$ ping baidu.com -s1024 -n # Baidu回复与Google不同PING baidu.com (220.181.111.86) 1024(1052) bytes of data.1032 bytes from 220.181.111.86: icmp_seq=1 ttl=53 time=7.11 ms$ ping yahoo.com -s1024 -n # 雅虎没响应；正常ping没问题PING yahoo.com (98.139.183.24) 1024(1052) bytes of data.