Finding Lost Changes with git fsck: A Git Tutorial


Git is a free and open-source distributed version control system designed to handle everything from small to large projects with speed and efficiency. With its ability to track changes in code over time, it has become an essential tool for developers and software engineers worldwide.

It allows multiple developers to work on the same project simultaneously, keeping track of changes, merging code from different sources, and rolling back changes when needed. Git works by creating a repository that contains all versions of a project’s files.

Users can make changes to their local copies of the files, which are then committed back into the repository when ready. The history of these changes is stored in the repository’s log, making it easy to revert back to previous versions should anything go wrong.

Explanation of How Changes Can Sometimes Get Lost in the Git Repository

Despite its robust version control capabilities, sometimes changes can get lost in a git repository. This can happen for several reasons such as accidental deletion or overwriting of commits, orphaned branches or objects not being properly referenced by any commits (dangling blobs), corrupt data or hardware failures.

When lost changes occur in a git repository, it can be frustrating and time-consuming for developers trying to recover them manually. However, with the help of Git fsck command line tool provided by git itself we could easily find such subtle details which might be missed out while recovering missing data manually.

Understanding how git works and what causes lost changes is essential for any developer who uses this powerful tool daily. In the following sections of this article we will explore how Git fsck command-line tool helps identify different types of lost objects present inside GIT database along with their possible recovery techniques which will ease down finding hard-to-find errors inside GIT database without doing much manual effort

Understanding Git fsck

Git is a vital tool in software development that enables developers to track changes made to their codebase over time. It provides an efficient way of managing and maintaining versions of software, making it easy to roll back changes, collaborate with other developers, and deploy new features.

However, as with any software tool, errors can sometimes occur, leading to lost changes in a repository. This is where git fsck comes into play.

Definition and Purpose of git fsck Command

Git fsck is a command-line utility that is used to find Git objects that are unreachable or lost within a repository. The name “fsck” stands for File System Consistency Check – the same name as the utility used by Unix-based systems to verify their file system integrity. When you run the git fsck command on your repository, it will scan through all the objects in your repository’s database and report any problems or inconsistencies it finds.

The purpose of git fsck is to help maintain the integrity and reliability of your Git repository by identifying problems before they have a chance to cause significant damage. By using this command regularly, you can detect potential issues early on and take appropriate action before permanent damage occurs.

Explanation of How It Works To Find Lost Changes

When you make changes in git, they are stored as commits within your repository’s database. Git keeps track of these commits using pointers called “refs.” These pointers point to specific commits within your codebase and allow you to access them quickly.

Sometimes these refs can become corrupted or lost due to various reasons such as hardware failure or accidental deletion. This can lead to situations where certain commits become “orphaned” – meaning they are no longer connected with any refs.

When you run git fsck on your repository, it searches for orphaned commits among other lost objects such as dangling blobs and orphaned branches. It then reports these objects as “unreachable” and provides information on how to restore them.

Git fsck is a powerful tool that helps maintain the integrity of your Git repository by detecting lost or unreachable commits and other objects. By regularly using this command, you can minimize the risk of losing valuable code changes and ensure that your repository remains reliable and consistent over time.

Types of Lost Changes

Exploring the Different Types of Lost Changes in Git Repository

Git is a powerful version control system that allows developers to track changes, collaborate, and revert changes if necessary. However, sometimes changes can get lost in the repository due to various reasons.

Understanding the different types of lost changes can help you identify and locate them more efficiently using git fsck. One type of lost change that often occurs in a git repository is deleted commits.

This happens when a commit is removed from the repository accidentally or intentionally without being merged with other commits, making it difficult or impossible to recover. Deleted commits can be caused by many reasons such as human error, conflicts during rebasing operations, or accidental deletion of a branch.

Another type of lost change is orphaned branches. These are branches that no longer have any parent commit in the repository’s history because they were created outside of any existing branch or were cut off from their parent branch due to rebasing operations.

Orphaned branches can be difficult to locate because they don’t have a clear relationship with other branches and may be invisible unless you use git fsck command. Dangling blobs are another type of lost change that can occur in a git repository.

Blobs are binary objects used for storing files within Git repositories. Dangling blobs refer to those objects that no longer point to any reachable tree object within the repository’s history due to multiple reasons like failed merge conflict resolution and improper handling during pull requests.

Examples of Lost Changes

Let’s take an example where one developer removes a feature branch before merging it into the mainline codebase—this could result in deleting some valuable commits necessary for further development efforts; hence those would be considered as deleted commits. Similarly, if someone merges their personal feature branch into master without pulling recent updates first then there may be additional orphaned commits that are no longer reachable.

A similar scenario can happen if someone deletes a branch locally, but the remote still has it. The removed branch will become an orphaned branch.

Dangling blobs arise when there is a merge conflict between two binaries, and the conflict resolution is done in incorrect ways such as accepting their changes without properly reviewing them. These types of changes can lead to data loss or inconsistencies among different developers working on the same codebase.

Identifying and understanding lost changes in a git repository can help prevent data loss and maintain consistency in your codebase. Knowing the different types of lost changes that usually occur in Git repositories allows you to take proactive steps to prevent them from happening or recover them quickly through git fsck command if they do occur.

Using Git fsck to Find Lost Changes

Step-by-step guide on how to use git fsck command to find lost changes

Git fsck is a powerful command that can help you locate lost changes in your repository. Here is a step-by-step guide on how to use git fsck:

1. Open your terminal and navigate to the root directory of your repository. 2. Enter the command: `git fsck –full`

3. Wait for the command to complete its scan of your repository. This may take some time depending on how large your repository is.

4. Once the scan is complete, look for any error messages that indicate lost or dangling commits, blobs, or trees. 5. Take note of the SHA-1 hash values associated with any lost changes.

Explanation on how to interpret the output from the command

The output from git fsck can be difficult to interpret if you are not accustomed to reading it. Here’s a breakdown of what you might see:

– “dangling commit”: indicates that a commit has been disconnected from its parent commit and is no longer reachable

– “dangling blob”: indicates that a blob (file) has been deleted but still exists in the repository – “dangling tree”: indicates that a file tree has been deleted but still exists in the repository

– “missing object”: indicates that an object (commit, blob, or tree) referenced by another object does not exist in the repository When using git fsck, it’s important to pay attention to these messages as they can help you locate lost changes.

It’s also worth noting that sometimes these messages may appear even if there are no actual lost changes in your repository; for example, if there are objects left over from an incomplete merge operation. Overall, it’s important to exercise caution when using git fsck and to consult the git documentation if you are unsure about how to interpret the output.

The Importance of Backing Up Your Repository

While git fsck can be a useful tool for locating lost changes, it’s always better to avoid losing changes in the first place. One way to do this is by backing up your repository regularly.

Backing up your repository can help ensure that you have a recent copy of all your changes in case something goes wrong. This can be especially important if you are working on a project with multiple collaborators or if you are frequently making changes to your codebase.

There are many ways to back up your repository, including using cloud storage services like Dropbox or Google Drive, setting up automatic backups using scripts or third-party tools, or manually copying your repository files to an external hard drive. Whatever method you choose, make sure that you have a reliable backup system in place so that you can easily recover any lost changes and get back to work as quickly as possible.

Restoring Lost Changes

After using the git fsck command to locate lost changes in your git repository, it’s important to restore them as soon as possible. Depending on the type of lost change that was found, there are different methods for restoring it. Here we will cover two common methods: cherry-picking commits and merging orphaned branches.

Cherry-picking Commits

If a lost commit has been found using git fsck, one way to restore it is by cherry-picking it into another branch. This can be done using the git cherry-pick command followed by the commit hash:

$ git cherry-pick <commit-hash>

This will apply the changes from the lost commit onto your current branch. Be sure to resolve any merge conflicts that arise before committing the changes. Cherry-picking is a useful tool for restoring individual changes that were lost, but if there were multiple commits that were lost, this process can become tedious and time-consuming.

Merging Orphaned Branches

If an orphaned branch was found using git fsck, merging it back into your main branch might be a better solution than cherry-picking each individual commit. To do this, first create a new branch from the orphaned commit:

$ git checkout -b <new-branch-name> <orphaned-commit-hash>

This will create a new branch starting at the orphaned commit. From here you can make any necessary changes before merging this branch back into your main branch:

$ git checkout <main-branch-name>

$ git merge <new-branch-name>

After resolving any merge conflicts that arise, commit the changes and push your updated repository to the remote branch.

Restoring lost changes using git fsck is an essential skill for any developer who uses git for version control. Whether you need to cherry-pick individual commits or merge orphaned branches, it’s important to act quickly to restore lost changes before they cause further issues down the line. By following these tips and best practices, you can ensure that your git repository stays organized and up-to-date.

Frequent Commits

One of the best ways to avoid lost changes in a git repository is to commit frequently. This means that you should be committing your changes as often as possible, rather than waiting until the end of a project or task to make a single large commit.

By committing frequently, you are creating a history of changes that can be easily tracked and managed over time, making it less likely that any particular change will get lost or overwritten. Another advantage of frequent commits is that they allow for easy rollbacks if something goes wrong.

If you make a mistake or run into an issue with your code, you can simply rollback to a previous commit and start again from there. This can save you a lot of time and effort in the long run, especially if you are working on complex projects with multiple contributors.

Descriptive Commit Messages

Another important best practice for avoiding lost changes is to use descriptive commit messages. A commit message should not only describe what changes were made, but also why those changes were made and how they impact the overall project or codebase.

This information will help future contributors understand why the change was made and how it fits into the larger context of the project. In addition, using descriptive commit messages can also help you keep track of your own work over time.

By providing detailed information about each change, you will be able to quickly identify which commits relate to which tasks or issues. This can be especially helpful when working on multiple projects simultaneously, or when returning to an older project after some time away.

Clear Git Workflow

Having a clear git workflow in place can also help prevent lost changes in your repository. This means establishing guidelines around when and how code should be committed and merged into the main branch, as well as who has access to make changes. By having a clear workflow in place, you can ensure that everyone on the team is following the same guidelines and best practices, which can help to minimize confusion and prevent mistakes.

One popular git workflow is the Gitflow Workflow, which defines specific branches for different stages of development (e.g., feature branches for individual tasks or issues, a develop branch for integration and testing, and a release branch for finalizing code before deployment). By following this type of workflow, you can create a well-organized repository with clear guidelines for how code should be managed and tracked over time.


Git fsck is an incredibly useful tool to have in your arsenal when working with git repositories. As we have seen, it can help you find lost changes that may have otherwise been very difficult to track down, and it can provide you with the information you need to restore those changes. By understanding the different types of lost changes that can occur and how git fsck helps in finding them, you will be able to use this command more effectively.

Remember to always be cautious when restoring changes and consider what impact they may have on your repository. We encourage you to use git fsck regularly as a preventative measure by checking for lost changes after any major updates or restructuring of your project.

This way, if any changes are missing or orphaned branches exist, they can be found quickly before they become a bigger problem later on. By utilizing git fsck as part of your regular workflow and following best practices for avoiding lost changes in the first place, you will be well-equipped to manage your git repository effectively and efficiently.

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