How to Undo a ‘git reset –hard’ Command

Overview

One of the most powerful and potentially dangerous commands in Git is the git reset --hard command. It effectively erases commits from your current branch, resetting your working directory to match a prior commit. If used without proper consideration, git reset --hard can lead to loss of data—specifically, uncommitted changes. In this tutorial, you’ll learn how to undo a git reset --hard action and recover your precious data.

Understanding the Risk of git reset --hard

Before we dive into how to reverse the effects of git reset --hard, let’s quickly understand what this command does. When you perform a git reset --hard, you are telling Git to:

• Move the HEAD and current branch pointer to the specified commit.
• Reset the staging index to match this commit.
• Reset the working directory so that all the tracked files match this commit.

This means all changes you made after the commit you reset to will be discarded—both staged and unstaged changes are lost.

Finding the Commit to Restore

The first thing you must do after performing an unintentional git reset --hard is to find the commit you wish to restore. Git does not erase commits immediately; it keeps them in a detached state for a while. To find these commits, you can use:

git reflog

The reflog preserves a history of the moves the HEAD and branch references have made in the repository. Check the output and locate the commit you need by looking at the messages next to each entry.

Expectations Before Undoing git reset --hard

Before you attempt to undo a git reset --hard, it’s crucial to understand:

• You can recover only changes that were committed at some point.
• Any uncommitted changes that were wiped out by the hard reset cannot be recovered using Git itself.

Recovering from a Hard Reset

So, you have located the commit to which you want to return. Now, to undo the git reset --hard, use:

git reset --hard <commit_hash>

Replace <commit_hash> with the actual hash of the commit you want to restore. After running this, your branch will be at the state you desire.

Advanced Recovery Using ORIG_HEAD

If you have not run any other destructive operations since the git reset --hard, Git provides a helpful reference called ORIG_HEAD, which points to the commit that was HEAD before the last command that moved it, which is potentially the commit before your --hard reset. To reset to it, use:

git reset --hard ORIG_HEAD

This command will revert the --hard reset if executed immediately after the unintended reset.

Using the reflog to Restore Lost Work

If you’re dealing with lost branches or more complex reset scenarios, locate the entry in the reflog where the branch was at the exact state you want:

git reflog show <branch_name>

Find the entry representing where your branch was before the hard reset and reset your branch to that commit:

git reset --hard <entry_commit>

This will put your branch back to the state before the accidental reset.

Creating a New Commit

If the reset tossed away changes you wanted to keep from the commits between your current state and the reset point, but you have now recovered the state of your repository, you can cherry-pick changes or manually copy them into your working directory and create a new commit using:

git add .
git commit -m "Recovered changes after accidental reset."

Dealing with Untracked Files

As mentioned, untracked files lost through git reset --hard cannot be recovered using Git tools. If you’ve lost such files, you’ll need to rely on external backups you may have, or file recovery tools that can scan your disk for remnants of the deleted files.

Limiting Future Risks

Now that you know how to recover from a git reset --hard, it’s wise to take steps to avoid the need to do so:

• Always ensure that your work is committed before executing any reset command.
• Create a backup branch before performing any history-rewriting operations.
• Consider using git stash to safely set aside changes without committing them.

Conclusion

Undoing a git reset --hard can feel daunting, but with the power of the reflog and careful attention to your repository’s state, it is usually possible to restore lost work. By understanding what this command does and how to navigate Git’s safety features, such as the reflog and ORIG_HEAD, you can recover from potentially catastrophic errors with confidence.