How to push to 2 repositories at the same time and keep them in sync

I had the need to have 2 GitHub repositories with the same exact content.

Whenever I pushed my changes, those changes had to be sent to those 2 repositories without any extra work.

So here’s what I did.

I already had a working repository with some code, set up as the origin remote in Git.

I created a new empty repository on GitHub, and I set is as another URL for the origin remote:

git remote set-url --add --push origin git@github.com:flaviocopes/original.git

git remote set-url --add --push origin git@github.com:flaviocopes/clone.git

That’s it. Now doing a “git push” sends the changes to both repositories.