判斷網線是否插入電腦

工具 ethtool

如果沒有安裝，則sudo apt-get install ethtool

終端運行 sudo ethtool eth0

結果1：（網線插入時）

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Supported
ports: [ TP MII ]

Supported
link modes: 10baseT/Half 10baseT/Full

100baseT/Half 100baseT/Full

1000baseT/Half 1000baseT/Full

Supports
auto-negotiation: Yes

Advertised
link modes: 10baseT/Half 10baseT/Full

100baseT/Half 100baseT/Full

1000baseT/Half 1000baseT/Full

Advertised
pause frame use: No

Advertised
auto-negotiation: Yes

Link
partner advertised link modes: 10baseT/Half 10baseT/Full

100baseT/Half 100baseT/Full

Link
partner advertised pause frame use: No

Link
partner advertised auto-negotiation: Yes

Speed:
100Mb/s

Duplex:
Full

Port:
MII

PHYAD:
0

Transceiver:
internal

Auto-negotiation:
on

Supports
Wake-on: pumbg

Wake-on:
g

Current
message level: 0x00000033 (51)

Link
detected: yes

結果2（網線拔除時）：

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Supported
ports: [ TP MII ]

Supported
link modes: 10baseT/Half 10baseT/Full

100baseT/Half 100baseT/Full

1000baseT/Half 1000baseT/Full

Supports
auto-negotiation: Yes

Advertised
link modes: 10baseT/Half 10baseT/Full

100baseT/Half 100baseT/Full

1000baseT/Half 1000baseT/Full

Advertised
pause frame use: No

Advertised
auto-negotiation: Yes

Link
partner advertised link modes: Not reported

Link
partner advertised pause frame use: No

Link
partner advertised auto-negotiation: No

Speed:
10Mb/s

Duplex:
Half

Port:
MII

PHYAD:
0

Transceiver:
internal

Auto-negotiation:
on

Supports
Wake-on: pumbg

Wake-on:
g

Current
message level: 0x00000033 (51)

Link
detected: no

可見可以根據grep"link detected: yes"的結果來判斷是否插入網線

shell 中寫下列代碼

ethtool eth0 | grep "Link detected: yes"
判斷一下上面這條命令的輸出就可以知道網線是不是接上了
if  上面的輸出為空白， 那麼網線就是沒有接上的
else 網線串連正常。