How do I fix add-apt-repository command “isn't supported” error in Ubuntu 18.04?

[springaprilday]

As a disclaimer: I'm really new at this so I may have have some trouble understanding advanced concepts. Thank you for your help and understanding.

I am trying to install Wine however when I run:
~~~
~$ sudo add-apt-repository 'deb https://dl.winehq.org/wine-builds/ubuntu/ cosmic main'
~~~

I get:
...LSB codename: 'bionic'.
This codename isn't currently supported.
Please check your LSB information with "lsb_release -a".
...

I've already tried (in order):
~~~
:~$ sudo apt-get install python3-software-properties
~$ sudo apt-get install apt-file
~$sudo apt install python-software-properties
~$ sudo apt-get update
~$ sudo apt-get install --reinstall python-software-properties
~$ sudo apt install --reinstall software-properties-common
~~~

(I followed the first two answers from <https://askubuntu.com/questions/38021/how-to-add-a-ppa-on-a-server>). When I search for add-apt-repository, I get:
~~~
~$ apt-file search add-apt-repository

software-properties-common: /usr/bin/add-apt-repository
software-properties-common: /usr/share/man/man1/add-apt-repository.1.gz
~~~

How do I get add-apt-repository to work?

[Dennis N]

Your command should end with 'bionic main', not 'cosmic main'
'cosmic' refers to Ubuntu 18.10

[again?]

You can add repository without using add-apt-repository.

Add 32bit architecture.
Add the signing key.

sudo dpkg --add-architecture i386
wget -qO - https://dl.winehq.org/wine-builds/winehq.key | sudo apt-key add -

Add the repository and update sources.

echo "deb https://dl.winehq.org/wine-builds/ubuntu/ bionic main" | sudo tee /etc/apt/sources.list.d/wine.list
sudo apt update
Use your release codename in above command.

lsb_release -cs

https://wiki.winehq.org/Ubuntu