Ubuntu Server ethernet

[xxteraxx]

I tried using ubuntu server so I can install i3 without any other desktop. I booted it up and plugged in my ethernet cable (Which did work on other installs of ubuntu) and no lights and my pc was not connected. I thought that I just had to put the interface up so I tried with Ifconfig and it said that the command ifconfig did not exist and I needed to install it. But how do I install net-tools without internet. Is there a way that i can connect without the use of ifconfig. (I'm using ethernet) because I really want to get it up and running. Any help would be much appreciated

Info: Ubuntu 20.04lts
hp 15-cs0022cl

[TheFu]

ifup/down has been deprecated for a few releases. Use the ip commands.
Ubuntu Server has been using netplan for ip/network configs since 17.10. That is the expected method on 20.04 server.

netplan config files go into /etc/netplan/. To get wired DHCP working,

network:
  version: 2
  renderer: networkd
  ethernets:
    enxcxxyyzzaabb:
      dhcp4: true
      dhcp6: false

This is a yaml file, so indentation is absolutely critical. Get that wrong and it won't work. Change the enxcxx... to be your ethernet device.
Then:

sudo netplan generate
sudo netplan apply --debug

Static ip setup is a little different.