How to delete historical commits in git

In recent years, Git, as a powerful version control tool, has become increasingly popular among development teams. However, when using Git, sometimes bad commits may appear, and these commits may have a negative impact on the project. How to delete these historical commits has become a problem often faced by Git users. This article will detail how to delete historical commits in Git.

1. Git submission history

Git submission history is composed of many submissions. Whenever you make a commit in Git, a new commit is created. Each submission has its own identifier (SHA) and contains information such as the submission's author, date, and description of the submission.

You can view the commit history in Git through the Git command line or Git client tool. For example, using the Git command line you can view the commit history of this project using the following command:

git log

This command will list all commits on the current branch, listed in reverse order. Each commit has its own SHA, committer's name and email, commit date, and commit message.

2. Why delete historical submissions

In the process of collaborative development, there will be many human factors that lead to the occurrence of bad submissions. "Bad Submissions" are Submissions that may contain errors, security vulnerabilities, sensitive information, etc. If these bad commits have been merged into the mainline branch, it may have a negative impact on other parts of the project.

In addition, if you include content that you do not want others to see before submitting the code, such as passwords, API keys and other sensitive information, it may be exposed after submission. At this time, deleting historical submissions is a way to protect user privacy.

3. How to delete historical commits in Git

In Git, there are two ways to delete historical commits: rewriting history and using Git's filtering mechanism.

1. Rewriting history

Rewriting history is actually achieved by modifying historical submissions. This means making changes and rearrangements to already published commits. The following are the steps to delete Git commit history:

(1) Use the following command to view the commit history:

git log

(2) Find the SHA of the commit you want to delete and record it.

(3) Use the following command to rewrite history. In this command, replace SHA with the SHA of the commit you want to delete:

git rebase -i SHA^

This command will open an editor with a list of all commits since the last commit of the selected commit.

(4) Change the "pick" in front of the commit to be deleted to "drop" or use the pound sign to comment out the line. Save and close the editor.

(5) Run the following command to force overwrite the commit in Git:

git push --force

Finally, you can use the following command to verify whether you successfully deleted the commit history:

git log

2. Using Git's filtering mechanism

In Git, the filter-branch command can help you delete commit history. This command copies the entire repository and applies the specified filter to each commit. The following are the steps to use Git's filtering mechanism to delete Git commit history:

(1) Use the following command to create a copy repository:

git clone --mirror <Git URL>

(2) Use the following command to enter the copy repository:

cd <repository name>.git

(3) Use the following command to delete historical submissions:

git filter-branch --force --index-filter "git rm --cached --ignore-unmatch <filename>" --prune-empty --tag-name-filter cat -- --all

This command is used to delete the historical submissions of the file named . This command can be changed as needed. Here, --tag-name-filter cat is used to fix tags. Finally, this command will be applied to all branches.

(4) Use the following command to push the changes to the Git repository:

git push --all --force

Finally, you can use the following command to verify whether the commit history is successfully deleted:

git log

four , Summary

You can delete historical commits in Git by rewriting history or using Git's filtering mechanism. However, before deleting commit history, you should think carefully and make sure all team members understand the impact of the change. Additionally, Git repositories should be cleaned regularly before merging changes to reduce storage overhead.

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