判断Linux服务器是否联网

$ ping www.baidu.com

PING www.a.shifen.com (14.215.177.39) 56(84) bytes of data.
64 bytes from 14.215.177.39 (14.215.177.39): icmp_seq=1 ttl=53 time=12.7 ms
64 bytes from 14.215.177.39 (14.215.177.39): icmp_seq=2 ttl=53 time=13.0 ms
64 bytes from 14.215.177.39 (14.215.177.39): icmp_seq=3 ttl=53 time=12.8 ms
64 bytes from 14.215.177.39 (14.215.177.39): icmp_seq=4 ttl=53 time=12.9 ms
64 bytes from 14.215.177.39 (14.215.177.39): icmp_seq=5 ttl=53 time=12.8 ms
64 bytes from 14.215.177.39 (14.215.177.39): icmp_seq=6 ttl=53 time=12.8 ms
64 bytes from 14.215.177.39 (14.215.177.39): icmp_seq=7 ttl=53 time=12.7 ms
64 bytes from 14.215.177.39 (14.215.177.39): icmp_seq=8 ttl=53 time=12.9 ms
64 bytes from 14.215.177.39 (14.215.177.39): icmp_seq=9 ttl=53 time=12.8

表示已经联网