ping -c(设置 ping 的次数，默认无限次，可选) -i(设置 ping 的时间间隔，默认1秒，可选) -W(设置 ping 的超时时间，可选) 192.168.0.1

# 直接 ping，无限次，1秒一次
$ ping 192.168.0.1
  PING 192.168.0.1 (192.168.0.1): 56 data bytes
  64 bytes from 192.168.0.1: icmp_seq=0 ttl=64 time=0.077 ms
  64 bytes from 192.168.0.1: icmp_seq=1 ttl=64 time=0.090 ms
  64 bytes from 192.168.0.1: icmp_seq=2 ttl=64 time=0.109 ms
  64 bytes from 192.168.0.1: icmp_seq=3 ttl=64 time=0.115 ms
  64 bytes from 192.168.0.1: icmp_seq=4 ttl=64 time=0.100 ms
  64 bytes from 192.168.0.1: icmp_seq=5 ttl=64 time=0.097 ms
  ......

# 指定 ping 6次就结束，1秒一次
$ ping -c6 192.168.0.1
  PING 192.168.0.1 (192.168.0.1): 56 data bytes
  64 bytes from 192.168.0.1: icmp_seq=0 ttl=64 time=0.077 ms
  64 bytes from 192.168.0.1: icmp_seq=1 ttl=64 time=0.090 ms
  64 bytes from 192.168.0.1: icmp_seq=2 ttl=64 time=0.109 ms
  64 bytes from 192.168.0.1: icmp_seq=3 ttl=64 time=0.115 ms
  64 bytes from 192.168.0.1: icmp_seq=4 ttl=64 time=0.100 ms
  64 bytes from 192.168.0.1: icmp_seq=5 ttl=64 time=0.097 ms

# 指定 ping 2次就结束，2秒一次
$ ping -c2 -i2 192.168.0.1
  PING 192.168.0.1 (192.168.0.1): 56 data bytes
  64 bytes from 192.168.0.1: icmp_seq=0 ttl=64 time=0.077 ms
  64 bytes from 192.168.0.1: icmp_seq=1 ttl=64 time=0.090 ms

# 指定 ping 超时时间
$ ping -W0.1 192.168.0.1
  PING 192.168.0.1 (192.168.0.1): 56 data bytes
# 直接就不通了，因为时间太短