How do I revert a Git repository to a previous commit?

How to Revert a Git Repository to a Previous Commit

Reverting a Git repository to a previous commit can be done in a few different ways depending on your needs. You might want to hard reset, soft reset, or create a new commit that undoes the changes. Below are the methods to achieve each of these goals.

1. Using git reset

Hard Reset

A hard reset will reset your working directory and the staging area to match a specific commit, effectively discarding all changes made after that commit. Use this with caution, as it will permanently delete uncommitted changes.

Command:

git reset --hard <commit_hash>

Example:

git reset --hard abc123

Soft Reset

A soft reset will reset the commit history to a specific commit but keep your changes in the working directory and the staging area. This is useful if you want to keep your changes but reset the commit history.

Command:

git reset --soft <commit_hash>

Example:

git reset --soft abc123

2. Using git revert

If you want to create a new commit that undoes the changes made by previous commits, use git revert. This is useful for maintaining a clear commit history.

Command:

git revert <commit_hash>

Example:

git revert abc123

You can also revert a range of commits:

git revert <oldest_commit_hash>^..<newest_commit_hash>

Example:

git revert abc123^..def456

3. Using git checkout (Detached HEAD State)

You can check out a specific commit to inspect the state of your repository at that point. This will put you in a "detached HEAD" state, meaning you are not on any branch.

Command:

git checkout <commit_hash>

Example:

git checkout abc123

If you want to make changes from this state, you should create a new branch:

git checkout -b new-branch-name

4. Resetting to a Previous Commit and Keeping Changes

If you want to reset to a previous commit but keep the changes from subsequent commits as unstaged changes, you can use a mixed reset.

Command:

git reset <commit_hash>

Example:

git reset abc123

Example Workflow

Suppose you want to reset your repository to a commit with hash abc123.

Hard Reset

git reset --hard abc123

Soft Reset

git reset --soft abc123

Revert to a Previous Commit

git revert abc123

Checkout a Specific Commit

git checkout abc123

Summary

• Hard Reset: Use git reset --hard <commit_hash> to discard all changes after a specific commit.
• Soft Reset: Use git reset --soft <commit_hash> to reset commit history but keep changes in the working directory.
• Revert: Use git revert <commit_hash> to create a new commit that undoes changes from a previous commit.
• Checkout: Use git checkout <commit_hash> to move to a specific commit in a detached HEAD state.

Choosing the appropriate method depends on your specific needs and whether you want to keep or discard changes after the specified commit. For more detailed tutorials and practical examples on Git and other coding practices, consider exploring Grokking the Coding Interview on DesignGurus.io, which offers comprehensive courses on essential coding and version control techniques.