How to get eth0 and wlan0 back on Ubuntu Mate 18.04?

[Bo Berglund]

I have a repurposed laptop running Ubuntu Mate 18.04.5 LTS and I need to run a
lot of scripts on this, but they fail because for some reason eth0 and wlan0 are
no longer available...

How can I re-enable the use of these standard names instead of the new strange
names?

I have searched the net and found some instructions here:
https://www.itzgeek.com/how-tos/mini-howtos/change-default-network-name-ens33-to-old-eth0-on-ubuntu-16-04.html

But the first part of this instruction is not clear since it says to "add" to
/etc/default/grub like this:


Look for “GRUB_CMDLINE_LINUX”  and add the following”net.ifnames=0
biosdevname=0“.

From:
GRUB_CMDLINE_LINUX=""
To:
GRUB_CMDLINE_LINUX="net.ifnames=0 biosdevname=0"


However, my existing entry is not empty, instead it has this:
GRUB_CMDLINE_LINUX="resume=UUID=<long guid string>"

So how can I handle the rename of the network and still not destroy whatever the
existing entry is meant to do?

I need to get back to eth0 and wlan0 for this machine...


-- 
Bo Berglund
Developer in Sweden