Sometime things go wrong… and sometimes things go terribly wrong. So you might find yourself in the depths of your favorite distribution’s recovery mode late in the night. Depending on the nature of your Linux distribution you might be served with the possibility to enable networking foresighted (e.g. via GRUB). Or… there is no such option at all and you are on your own to figure out how to fix your failed update, missing dependencies or incompatible packages — all that, without the plethora of solutions offered by the almighty internet.
Fortunately there is a straight-forward way to get your Ethernet bits flowing:
ifconfig eth0 up
dhclient eth0
# Validate local IP / network config
ifconfig