# Pipeline tutorial: transitioning from `master` to `main` branches

> [!WARNING]
> Make sure you are on using same version of nf-core/tools as the template version of your branch

## Prequisites

- Admin rights on the GitHub repository where the change taking place
- nf-core tools
- It is recommended that the version match the version of the template in your pipeline

## Instructions

1. Open your repository (make sure you're on master)
2. Go to the `branches` page (to the right of the `branches` drop down where it says 'master')
3. Under the default branch section of the page, press the triple dot menu on the `master` branch row, and press 'Rename branch'
4. Rename `master` to `main`
5. Press the 'learn more' text, and copy and paste the displayed instructions somewhere safe,
6. Press 'Rename branch'
7. Go back to 'Code' tab to verify you are now on `main`
8. In your local IDE (e.g. VSCode) make sure you're on the `dev` branch
9. Run `git pull` or `git pull` to ensure you have the `main` branch locally
10. Check your `git` config to see what is your current default branch (it should report `master`):

      git config --global init.defaultBranch

12. Change it to `main` with :

      git config --global init.defaultBranch main

14. Check your `git` config again to check it change (it should now report `main`):

      git config --global init.defaultBranch

15. Still on `dev`, run `nf-core pipelines sync`
16. Change to a new branch `git switch -c default-branch-change`
17. Follow the merge TEMPLATE instructions, i.e. `git merge TEMPLATE`
- If you don't want any other template changes, make sure to use `nf-core/tools` version that matches the template version in your pipeline
18. Resolve merge conflicts (if just ROcrate, accept all incoming chagnes
19. Check that all references of your pipelines' `msater` is now `main` using a global repository search in your IDE
> [!WARNING]
> Make sure not to modify references of master in links to other repositories!
> If in doubt, ask on the nf-core slack!
20. Run `nf-core pipelines lint` to check you didn't break anything
21. Commit and merge `git add -am 'Change default branch'
22. Push the changes `git push`
23. On GitHub make a new PR against `dev`
24. Review PR to check all links and `nextflow.config` manifest say `main`
25. Review and merge

## Post-change instructions

1. Inform all your collaborators (on slack, etc.) that the default branch has changed, and that they should update their clones and forks, i.e.:

    git branch -m master main
    git fetch origin
    git branch -u origin/main main
    git remote set-head origin -a
  

2. Update your own clones and forks