How to remove apt repository on ubuntu 18?

[Bo Berglund]

My server runs Ubuntu Server 18.04.5 LTS (GNU/Linux 4.15.0-153-generic x86_64)

Some time ago I used these directions to install streamlink via apt:
https://streamlink.github.io/install.html#linux-and-bsd

It involved first adding a repository to apt as follows:

sudo add-apt-repository ppa:nilarimogard/webupd8

Then normal update and install.

But this gets an *old* version of streamlink so I found that using pip would get
me the latest version instead.

But after using pip there are two versions of streamlink on my system so I
decided to run:

sudo apt remove streamlink
and it worked to get rid of the apt installed streamlink.

But now I also want to get rid of the repository I added to apt in order to get
streamlink.

How can this be done?
Is there a corresponding remove command for apt repositories?


-- 
Bo Berglund
Developer in Sweden