I am curious about how to remove the first commit in git.
What is the revision before committing any thing? Does this revision have a name or tag?
For me, the most secure way is to use the update-ref command:
git update-ref -d HEAD
It will delete the named reference HEAD, so it will reset (softly, you will not lose your work) all your commits of your current branch.
If what you want is to merge the first commit with the second one, you can use the rebase command:
git rebase -i --root
A last way could be to create an orphan branch, a branch with the same content but without any commit history, and commit your new content on it:
git checkout --orphan <new-branch-name>
There is nothing before the first commit, as every commit is referring a parent commit. This makes the first commit special (an orphan commit), so there is no way to refer to a previous "state".
So if you want to fix the commit, you can simply git commit --amend: this will modify the commit without creating another one.
If you just want to start all over, delete the .git repository, and make another one with git init
Check out to a temporary branch:
git checkout --orphan TEMP_BRANCH
Add all the files:
git add -A
Commit the changes:
git commit -am "Initial commit"
Delete the old branch:
git branch -D master
Rename the temporary branch to master:
git branch -m master
Finally, force update to our repository:
git push -f origin master
You might just want to edit your first commit (as there is always a first commit in a git repo). Consider using git commit --amend --reset-author instead of the usual git commit --amend.
Another way you can do is:
- Checkout to a branch you want to keep (say dev)
git checkout dev - Now, delete the branch you want to reset
git branch -D master - Now, create an empty branch with the same name
git checkout --orphan master
Ofcourse, all of this would depend on your usecase, but if you have more than one branch, deleting the .git directory does not make sense.
If you want to keep other branches, but for example make the master branch start anew without common history to other branches, one safe way to achieve this is to create a new repository, and push contents of that in your old one:
cd ..
git init newrepo
cd newrepo
# make some initial commits
git push ../oldrepo master:newmaster
This creates newmaster branch in the old repository, with history that is not common with any of the other branches. Of course, you can just overwrite the master as well, with git push -f.
If you want to destroy all branches and all existing content, then just run
rm -rf .git/
If you have just committed it but not pushed it then just remove .git directory and git init again...
The answer to the question depends on whether:
You want to remove the first AND ONLY commit on a branch (whilst leaving other branches as they were), or whether
You want to remove the first commit on some branch, whilst 'leaving in place' the subsequent commits (and the other branches).
The second of these is relatively simpler. You essentially have to rebase on to root - most of the answers here are about ways to do this.
To do the second (removing the first and only commit from a branch whilst leaving other branches alone) is harder. Or, at least, especially harder if you want it to happen and for the change to be reflected back in GitHub or Bitbucket. There is (as far as I can tell) no way at all in Git to push or force push a branch with no commits. And there is also (again, as far as I can see) no way at all to create a new, empty branch with no commits on it in either GitHub or Bitbucket. So you essentially have to create a new repository in order to create a completely empty branch, and then add back the branches which you want (including the commits which you want) - as per @user1338062's answer.
So I hope this answer clarifies what might not have been obvious - that there are two different approaches that need to be taken, for two different (more or less reasonable) scenarios which are both things you might want to be able to do, in order to fully master doing what the OP asks.
来源：https://stackoverflow.com/questions/10911317/how-to-remove-the-first-commit-in-git