See also Git branches in a nutshell
Make liberal use of local branches to get the hang of making and committing changes, merging from upstream, or merging or rebasing across branches in your local repository.
In this class, if you maintain your master branch well, it is the best
starting point for new branches, including feature branches for assignment
submissions and experimental branches on which to practice.
First check what branch you are currently on:
git status
Then, if not already on master change to it:
git checkout master
Then, create your new branch:
git checkout -b my-experimental-branch
Branches are cheap and easy to make, so get the hang of creating new ones, trying things out, and destroying any that don't work.
When finished with a branch, you can delete it with:
git branch -d branchname
So long as changes from branchname have been fully merged upstream or in
HEAD this will quietly succeed. Otherwise, it will fail with an error to
prevent you from deleting unsaved work.
If you have some dead-end branch containing changes that you do not want to keep, use
git branch -D branchname
to force the issue. But just be sure you don't want stuff from that branch.
If you force delete a branch with -D you force delete your changes in real life.
Blowing away just a couple of experimental branches in which everything has gone wrong is much better than deleting your entire repository and starting over.
So long as
git status
shows you on an experimental branch, you can bail out in any of a number of ways. Bail out of a bad rebase with
git rebase --abort
Bail out of a bad merge with
git merge --abort
Or you can use git reset in various ways.
So long as you're on an experimental branch and are committed to blowing it away anyway, you can even go forward and out instead of trying to back up. Add all your changes to the branch, then commit them:
git checkout -b my-horrible-experiment
[ ... do bad stuff that doesn't work ... ]
git add bogusfile1 messedupfile.txt nastyconflictinside.md
git commit -m "these are all horrible"
git checkout some-clean-branch
git branch -D my-horrible-experiment
Git doesn't care if you add and commit them only then to delete them. It won't judge you, and if you never merge the branch nor push it upstream, no one else has to know.