Revisiting Basic Git Commands and Troubleshooting GitHub SSH Authentication

Note: This post is part of refreshing Git push errors and SSH key authentication error issues. This learning post is still in active development and updated regularly.

I hadn’t used my GitHub repository for a while. Recently, I decided to start creating blueprints for my WP Playground to test the upcoming features in WordPress 6.6 and streamline my starter theme development workflow.

Usually, when there’s a new feature to test, I set up a new Local site on my browser and add theme test/dummy data to experiment with. But now, with WP Playground’s new feature, I can spin up a temporary playground site directly in the browser and get right to work.

However, when I started working with a new GitHub repository, I realized that my Git knowledge had gotten a bit rusty. The SSH authentication key for my computer and GitHub repository had become outdated due to updates, so I needed to tackle that issue and refresh my basic Git knowledge first.

During this process, I encountered various issues when trying to push my changes to GitHub. Here’s a comprehensive reminder guide for myself for troubleshooting these common Git push errors issues:

The authenticity of host 'github.com (140.82.112.4)' can't be established.
ED25519 key fingerprint is SHA256:+DiY3wvvV6TuJJhbpZisF/zLDA0zPMSvHdkr4UvCOqU.
This key is not known by any other names.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added 'github.com' (ED25519) to the list of known hosts.
git@github.com: Permission denied (publickey)

After spending almost a day in google searching for the solutions, I decided to use ChatGPT-40 if that can be of help. I posted the entire error message on the ChatGPT message page, here is what I got from the ChatGPT, which eventually troubleshoot my machine authentication problem.

Step-by-Step Process to Fix the SSH Key Issues

1. Ensure SSH Agent is Running: First, make sure the SSH agent is running and has your key added.

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_rsa

2. Verify the SSH Key: Make sure your SSH key is added to your GitHub account. You can verify this by checking the contents of your public key and comparing it with the SSH keys listed in your GitHub settings

cat ~/.ssh/id_rsa.pub

Copy the output and go to GitHub SSH and GPG keys settings to ensure the key is added there.

3. Add SSH Key to GitHub: If your key is not added, follow these steps to add it and Copy your public SSH key:

cat ~/.ssh/id_rsa.pub
  • Go to GitHub SSH and GPG keys settings.
  • Click “New SSH key”.
  • Paste your key into the “Key” field.
  • Give it a title (like “My Computer”) and click “Add SSH key”.

4. Test the SSH Connection: After adding your SSH key to GitHub, test the connection again:

ssh -T git@github.com

You should see a message like:

Hi username! You've successfully authenticated, but GitHub does not provide shell access.

5. Push Your Changes: Now that your SSH key is correctly set up, you should be able to push your changes to GitHub.

git push -u origin main

I got the src refspec main does not match any error message.

The SSH connection is success, but when I push I get this message <error: src refspec main does not match any
error: failed to push some refs to 'origin'
Troubleshooting mismatch local and remote branch issues

To resolve the issue, I posted the entire error message on the ChatGPT message board, and I got the following answer from the ChatGPT.

The error message src refspec main does not match any indicates that Git cannot find the branch named main in your local repository. This can happen if the branch does not exist or if there is a naming mismatch. Let’s resolve this step by step.

1. Check Your Local Branch: First, verify the branches in your local repository:

git branch 

If you see master but not main, it means your default branch is named master.

2. Rename the Branch to main (if necessary): If your branch is named master and you want to push to main, you need to rename it:

git branch -m master main

3. Set the Upstream Branch: After renaming, set the upstream branch and push:

git push -u origin main

4. If You’re Using master as Your Main Branch: If you prefer to use master as your main branch, simply push it without renaming:

git push -u origin master

Additional checks:

  • Ensure that your remote repository on GitHub has the correct default branch settings.
  • If your GitHub repository default branch is main, use main; if it’s master, use master.
Checking how remote repository is set up

Here are the steps to troubleshoot and fix the error message fatal: 'origin' does not appear to be a git repository issue.

1. Check Remote Repositories: First, check if any remote repositories are configured:

git remote -v

2. Add the Remote Repository: If no remote named origin is listed, you need to add it. Replace YOUR_GITHUB_USERNAME and YOUR_REPOSITORY with your actual GitHub username and repository name.

git remote add origin git@github.com:YOUR_GITHUB_USERNAME/YOUR_REPOSITORY.git

3. Verify the remote URL: Ensure the remote URL is set correctly:

git remote -v

The output should be something like this:

origin  git@github.com:YOUR_GITHUB_USERNAME/YOUR_REPOSITORY.git (fetch)
origin  git@github.com:YOUR_GITHUB_USERNAME/YOUR_REPOSITORY.git (push)

4. Push to the remote repository: Now, you should be able to push your local branch to the remote repository:

git push -u origin master

This should resolve the issue and allow you to push your local repository to GitHub. Indeed! it resolved the issue.

Wrapping up

The ChatGPT-4o could potentially provide helpful assistance instead of wasting time searching for answers via Google. In the next post, I will document Git push errors.

NEXT POST: Troubleshooting Git Push Errors: A Step-by-Step Guide

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