判断网线是否插入电脑

工具 ethtool

如果没有安装，则sudo apt-get install ethtool

终端运行 sudo ethtool eth0

结果1：（网线插入时）

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Supportedports: [ TP MII ]

Supportedlink modes: 10baseT/Half 10baseT/Full

100baseT/Half 100baseT/Full

1000baseT/Half 1000baseT/Full

Supportsauto-negotiation: Yes

Advertisedlink modes: 10baseT/Half 10baseT/Full

100baseT/Half 100baseT/Full

1000baseT/Half 1000baseT/Full

Advertisedpause frame use: No

Advertisedauto-negotiation: Yes

Linkpartner advertised link modes: 10baseT/Half 10baseT/Full

100baseT/Half 100baseT/Full

Linkpartner advertised pause frame use: No

Linkpartner advertised auto-negotiation: Yes

Speed:100Mb/s

Duplex:Full

Port:MII

PHYAD:0

Transceiver:internal

Auto-negotiation:on

SupportsWake-on: pumbg

Wake-on:g

Currentmessage level: 0x00000033 (51)

Linkdetected: yes

结果2（网线拔除时）：

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Supportedports: [ TP MII ]

Supportedlink modes: 10baseT/Half 10baseT/Full

100baseT/Half 100baseT/Full

1000baseT/Half 1000baseT/Full

Supportsauto-negotiation: Yes

Advertisedlink modes: 10baseT/Half 10baseT/Full

100baseT/Half 100baseT/Full

1000baseT/Half 1000baseT/Full

Advertisedpause frame use: No

Advertisedauto-negotiation: Yes

Linkpartner advertised link modes: Not reported

Linkpartner advertised pause frame use: No

Linkpartner advertised auto-negotiation: No

Speed:10Mb/s

Duplex:Half

Port:MII

PHYAD:0

Transceiver:internal

Auto-negotiation:on

SupportsWake-on: pumbg

Wake-on:g

Currentmessage level: 0x00000033 (51)

Linkdetected: no

可见可以根据grep"link detected: yes"的结果来判断是否插入网线

shell 中写下列代码

ethtool eth0 | grep "Link detected: yes"
判断一下上面这条命令的输出就可以知道网线是不是接上了
if  上面的输出为空， 那么网线就是没有接上的
else 网线连接正常。