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

To revert a Git repository to a previous commit, you can use one of the following methods depending on your goal:

1. Reset to a Previous Commit (Destructive)

Use git reset to remove commits from the branch history (ideal for local/unpushed changes).

# Replace `<commit-hash>` with the target commit ID (e.g., abc123)
git reset --hard <commit-hash>

Example:

git reset --hard abc1234   # Discard all commits after abc1234

Notes:

• --hard: Discards all changes in the working directory and staging area.
• Use git reflog to recover lost commits if you reset accidentally.
• Avoid this for pushed commits (rewrites history; use git push --force cautiously if needed).

2. Revert to a Previous Commit (Non-Destructive)

Use git revert to undo changes from specific commits while preserving history (safe for public/shared branches).

git revert <commit-hash>   # Reverts a single commit
# OR
git revert HEAD~3..HEAD    # Reverts the last 3 commits

Example:

git revert abc1234         # Creates a new commit undoing abc1234

Notes:

• This creates new commits that reverse the changes.
• Use git revert --no-commit to combine multiple reverts into a single commit.

3. Check Out a Previous Commit (Temporary)

Check out a specific commit without altering the branch (creates a detached HEAD state):

git checkout <commit-hash>

To save changes from this state:

git checkout -b new-branch-name   # Create a new branch from the old commit

Key Differences

Method	Use Case	History Impact
git reset	Discard local/unpushed commits.	Rewrites history (destructive).
git revert	Undo pushed commits safely.	Preserves history (non-destructive).
git checkout	Temporarily inspect old code.	No permanent changes.

Step-by-Step Workflow

Reset to a Previous Commit

1. Find the target commit hash:

   git log --oneline   # Copy the commit hash (e.g., abc1234)

2. Reset to that commit:

   git reset --hard abc1234

Revert a Specific Commit

1. Identify the commit to undo:

   git log --oneline   # Find the commit hash (e.g., def5678)

2. Revert it:

   git revert def5678

Important Notes

• Backup Changes: Use git stash before resetting to save uncommitted work.
• Collaboration: Avoid git reset on shared branches (use git revert instead).
• Recovery: Use git reflog to recover lost commits after a git reset.

By choosing the right method, you can safely roll back your Git repository!