How to detect the physical connected state of a network cable/connector?

Question

In a Linux environment, I need to detect the physical connected or disconnected state of an RJ45 connector to its socket. Preferably using BASH scripting only.

The

Answer 1

Most modern Linux distributions use NetworkManager for this. You could use D-BUS to listen for the events.

If you want a command-line tool to check the status, you can also use mii-tool, given that you have Ethernet in mind.