Resolving Permission denied (publickey) Error While Cloning Git Repositories on Ubuntu

Learn how to fix the common GitHub SSH access issue when cloning repositories on Ubuntu. Troubleshoot the `Permission denied (publickey)` error effectively with simple steps.
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This video is based on the question https://stackoverflow.com/q/65524600/ asked by the user 'nightfarrow' ( https://stackoverflow.com/u/14915891/ ) and on the answer https://stackoverflow.com/a/65525020/ provided by the user 'bk2204' ( https://stackoverflow.com/u/8705432/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the Problem: Permission denied (publickey) Error

If you have ever attempted to use the git clone command and encountered the message "Permission denied (publickey). fatal: Could not read from remote repository.", you're not alone. This specific error usually indicates that there's a problem with your SSH key configuration or how you're trying to access the repository.

Background

After you have set up Git and SSH on your Ubuntu system, you might feel confident that everything is in order. However, using sudo in conjunction with SSH operations can cause issues that prevent access to your GitHub repositories.
In this guide, we will break down why this happens and how to effectively resolve the error.

Solution Breakdown: Diagnosing and Fixing the Issue

Reason Behind the Error

When you run the git clone command with sudo, several important changes occur:

User Context Shift: Using sudo switches the user context to the root user. Thus, any SSH keys associated with your default user won't be accessible.

Environment Clearing: By default, sudo clears the environment variables, which includes access to your SSH agent. This allows only root to access its own SSH keys, resulting in denied permission when trying to connect to GitHub.

Recommended Solution

Instead of using sudo, consider these alternatives:

Avoid Using sudo

Most git operations do not require root access, especially cloning repositories. Attempt to run your git clone command regularly without sudo:

[[See Video to Reveal this Text or Code Snippet]]

Using sudo -E (If Absolutely Necessary)

If you are certain that you need sudo for specific reasons and there are no security risks involved, you can allow the SSH agent to work with the following command:

[[See Video to Reveal this Text or Code Snippet]]

The -E flag preserves the user’s environment, giving the SSH agent access to your keys.

Confirming SSH Keys and Access Rights

To ensure everything is configured correctly, double-check the following:

SSH Key Generation: Verify you have created your SSH key correctly using:

[[See Video to Reveal this Text or Code Snippet]]

Ensure the public key id_ed25519.pub is copied to your GitHub account under SSH keys.

SSH Agent Running: Confirm that your SSH agent is running and your key is added with:

[[See Video to Reveal this Text or Code Snippet]]

Testing SSH Connection: Run:

[[See Video to Reveal this Text or Code Snippet]]

You should see a message indicating successful authentication. If you see the message stating you've authenticated but GitHub doesn't provide shell access, that's a normal response confirming the validity of your keys.

Conclusion

Troubleshooting the Permission denied (publickey) error when cloning GitHub repositories on Ubuntu requires some understanding of how SSH operates within different user contexts. By being mindful of when to use sudo and ensuring your SSH keys are configured properly, you can effectively eliminate this issue and streamline your Git workflow.

Now you're equipped with the knowledge to handle this common problem and can continue your development work without interruptions. Happy coding!