How to determine the Link Speed or Network speed of a Network Adapter in Ubuntu
In order to determine the Link Speed or the Network Speed of a Network adapter in Ubuntu, simple open up a terminal window and issue the following command:
Here eth0 is your adapter name, it can be different than eth0. If you want to find out what your ethernet adapter is called give the following command
This will show you all the network adapters in your Ubuntu machine along with their names.