Thanks! So that would be sudo ifconfig ethX up or sudo ifconfig "ethX" "up"?
I just copied the content of interfaces from my main machine
(without even checking the number of the eth interface, which would have
probably been a bit troublesome on another network)
auto ethX
iface ethX inet dhcp
If I understand properly, the dhclient command sets ethX as dhcp instead of
nothing (not even a static IP address)?
But it's very interesting (and needed, for identifying the interface's name)
to see how to do so from commands only.