Push local git commits to pre-existing remote repo

I had to look this up recently when pushing a local git repo to a remote repo on GitHub that I'd already set up with a LICENSE.md file that wasn't stored locally.

Because the remote repo wasn't empty, I needed to rebase and allow unrelated histories to merge.

So, in the project directory, we first stage and commit local files:

git add .
git commit -m "My local commit"

Add the GitHub repository as a remote (replacing correct REMOTE_URL value):

git remote add origin <remote-url.git>

Verify the remote was added correctly:

git remote -v

Now: pull changes from the remote repository with --rebase and --allow-unrelated-histories flags:

git pull --rebase origin main --allow-unrelated-histories

Because the remote repository has existing files, local and remote histories are unrelated. So this command pulls the remote's changes and allows a merge with your local project, rebasing the repo to create a linear history. It's effectively as if the remote files always existed, and local changes were made on top of them.

Finally, push the rebased local repo upstream to origin:

git push -u origin main

All local files and the remote repository files should now be merged and synchronized.