Git SSH Configuration

In GitHub, configuring SSH is primarily done to securely access and operate GitHub repositories using SSH keys. Here are the steps to configure GitHub SSH:

1. Check if you already have SSH keys

First, check if you already have SSH keys. If you are unsure, you can use the following command to view if you have existing keys:

ls -al ~/.ssh

Check if there is a file named id_rsa or id_ed25519, if not, generate a new key.

2. Generate a new SSH key

If you don’t have existing SSH keys, you can use the following command to generate a new key:

ssh-keygen -t rsa -b 4096 -C "your_email@example.com"

• -t rsa means using RSA algorithm.
• -b 4096 means the key length (4096 is a secure choice).
• -C "your_email@example.com" is the comment for the key, usually use your GitHub email.

When prompted, press Enter to accept the default location (usually ~/.ssh/id_rsa). If you want to set a passphrase, you can enter it when prompted, or press Enter to skip it.

3. Add the SSH key to the SSH agent

To avoid entering a password each time you perform an operation, you can add the SSH key to the SSH agent:

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

4. Add the SSH public key to GitHub

Next, add the public key to GitHub:

1. Copy the content of the public key (usually the content of ~/.ssh/id_rsa.pub or ~/.ssh/id_ed25519.pub file). You can use the following command to view and copy:

   cat ~/.ssh/id_rsa.pub
   

2. Login to your GitHub account, enter Settings -> SSH and GPG keys -> New SSH key.
3. Fill in a recognizable name (e.g., “My Mac”) in the “Title” field, paste the public key content you copied earlier, and click Add SSH key.

5. Test SSH connection

Ensure the SSH configuration is correct, you can use the following command to test the connection:

ssh -T git@github.com

If it is the first time connecting, the system will prompt you whether to trust the GitHub server, input yes.If everything is normal, you will see something like:

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

6. Configure Git to use SSH

Ensure Git uses SSH for repository operations. Check if the remote URL of the repository is an SSH address instead of HTTPS:

git remote -v

If it is a HTTPS address, you can modify it to an SSH address:

git remote set-url origin git@github.com:username/repository.git