How to Set Up an SSH Key for Git?

Using an SSH key with Git is one of the most secure and convenient ways to authenticate with your Git repositories. By configuring SSH, you eliminate the need to enter your username and password every time you interact with remote repositories, making your workflow smoother while maintaining robust security.

In this blog, we’ll walk through the process of generating, adding, and using an SSH key for Git.

What Is an SSH Key?

SSH (Secure Shell) keys are a pair of cryptographic keys—a private key stored securely on your machine and a public key shared with remote servers like GitHub, GitLab, or Bitbucket. These keys are used to establish a secure connection between your computer and the remote server.

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Step-by-Step Guide to Setting Up an SSH Key for Git

Step 1: Check for Existing SSH Keys

Before creating a new SSH key, check if you already have one.

1. Open your terminal or Git Bash.
2. Run the following command to list existing SSH keys:

   ls -al ~/.ssh

3. If you see files like id_rsa and id_rsa.pub, you already have an SSH key. You can skip to Step 3 to add the key to your Git account.

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Step 2: Generate a New SSH Key

If no keys exist, generate a new one.

1. Run the following command:

   ssh-keygen -t rsa -b 4096 -C "[email protected]"

Replace [email protected] with the email address associated with your Git account.

2. When prompted:

• Press Enter to save the key to the default location (~/.ssh/id_rsa).
• Optionally, enter a passphrase for added security. Press Enter if you prefer no passphrase.

2. After completing these steps, two files will be created:

• id_rsa (private key)
• id_rsa.pub (public key)

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Step 3: Add the SSH Key to the SSH Agent

To use your SSH key, you need to add it to the SSH agent.

1. Start the SSH agent:

   eval "$(ssh-agent -s)"

2. Add your private key to the agent:

   ssh-add ~/.ssh/id_rsa

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Step 4: Add the SSH Key to Your Git Account

The final step is to upload your public key to the remote Git server (e.g., GitHub, GitLab, or Bitbucket).

For GitHub

1. Copy the contents of your public key:

   cat ~/.ssh/id_rsa.pub

Copy the output to your clipboard.

2. Log in to your GitHub account.
3. Navigate to Settings > SSH and GPG keys.
4. Click New SSH Key.
5. Paste the key into the “Key” field and give it a descriptive title (e.g., “Work Laptop”).
6. Click Add SSH Key.

For GitLab

1. Copy your public key using the same command as above:

   cat ~/.ssh/id_rsa.pub

2. Log in to your GitLab account.
3. Navigate to Preferences > SSH Keys.
4. Paste the key and click Add Key.

For Bitbucket

1. Copy your public key:

   cat ~/.ssh/id_rsa.pub

2. Log in to your Bitbucket account.
3. Go to Personal Settings > SSH Keys.
4. Click Add Key, paste the key, and save.

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Step 5: Test the SSH Connection

Verify that the SSH key is configured correctly by testing the connection to the remote server.

For GitHub

Run:

ssh -T [email protected]

Expected output:

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

For GitLab

Run:

ssh -T [email protected]

For Bitbucket

Run:

ssh -T [email protected]

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Step 6: Configure Git to Use SSH

To ensure Git uses SSH for all interactions with your remote repositories, update the repository’s URL to the SSH format.

1. Check the current remote URL:

   git remote -v

2. Update the URL to the SSH format (e.g., [email protected]:username/repository.git):

   git remote set-url origin [email protected]:username/repository.git

3. Verify the updated URL:

   git remote -v

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Benefits of Using SSH with Git

• Enhanced Security: SSH keys are harder to compromise than traditional username-password authentication.
• Convenience: No need to enter credentials repeatedly.
• Automation: Ideal for automated scripts or CI/CD pipelines where manual input is impractical.

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Troubleshooting SSH Issues

• Permission Denied Errors:
  Ensure the private key is added to the SSH agent and the public key is uploaded to the Git server.
• Key Not Found:
  Verify the key files are stored in the ~/.ssh directory and have correct permissions:

  chmod 600 ~/.ssh/id_rsa
  chmod 644 ~/.ssh/id_rsa.pub

• Multiple SSH Keys:
  If using multiple SSH keys (e.g., for work and personal accounts), create an SSH config file:

  Host github.com-work
      HostName github.com
      User git
      IdentityFile ~/.ssh/id_rsa_work
  Host github.com-personal
      HostName github.com
      User git
      IdentityFile ~/.ssh/id_rsa_personal

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Conclusion

Setting up an SSH key for Git is a straightforward process that enhances both the security and convenience of your development workflow. By following this guide, you can seamlessly interact with Git repositories while keeping your authentication secure.

Once configured, you’ll save time and effort, allowing you to focus on writing code and collaborating with your team.