How do you roll back (reset) a Git repository to a particular commit?
Update:
Because of changes to how tracking branches are created and pushed I no longer recommend renaming branches. This is what I recommend now:
Make a copy of the branch at its current state:
git branch crazyexperiment
(The git branch <name> command will leave you with your current branch still checked out.)
Reset your current branch to your desired commit with git reset:
git reset --hard c2e7af2b51
(Replace c2e7af2b51 with the commit that you want to go back to.)
When you decide that your crazy experiment branch doesn't contain anything useful, you can delete it with:
git branch -D crazyexperiment
It's always nice when you're starting out with history-modifying git commands (reset, rebase) to create backup branches before you run them. Eventually once you're comfortable you won't find it necessary. If you do modify your history in a way that you don't want and haven't created a backup branch, look into git reflog. Git keeps commits around for quite a while even if there are no branches or tags pointing to them.
Original answer:
A slightly less scary way to do this than the git reset --hard method is to create a new branch. Let's assume that you're on the master branch and the commit you want to go back to is c2e7af2b51.
Rename your current master branch:
git branch -m crazyexperiment
Check out your good commit:
git checkout c2e7af2b51
Make your new master branch here:
git checkout -b master
Now you still have your crazy experiment around if you want to look at it later, but your master branch is back at your last known good point, ready to be added to. If you really want to throw away your experiment, you can use:
git branch -D crazyexperiment
git reset --hard <tag/branch/commit id>
Notes:
git resetwithout the--hardoption resets the commit history, but not the files. With the--hardoption the files in working tree are also reset. (credited user)If you wish to commit that state so that the remote repository also points to the rolled back commit do:
git push <reponame> -f(credited user)