Setting up SSH and Git on MacOS

After receiving my new Macbook, I started setting up a development environment on MacOS. To set up Git on MacOS, I generated a new SSH key on my Mackbook and added it to my GitHub account to enable authentication for Git operations over SSH.

1. Generating a new SSH key

I open a terminal and paste the text below to generate a new SSH key:

ssh-keygen -t ed25519 -C "your_email@example.com"
Generating public/private ed25519 key pair.
Enter file in which to save the key (/Users/shenlu/.ssh/id_ed25519):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /Users/shenlu/.ssh/id_ed25519
Your public key has been saved in /Users/shenlu/.ssh/id_ed25519.pub
The key fingerprint is:
SHA256:kWkioRYSeKUUpNBRckvF/JGfJ+wfcu2FrtE6/TYgrr0 your_email@example.com
The key's randomart image is:
+--[ED25519 256]--+
|=+B=*+.  .       |
|o+oB oo oo       |
|..+ o ..=+ .     |
| .   . o..= .    |
|        S. o . . |
|          o.ooo .|
|          .+o=o. |
|          ..oo+..|
|         ..E+o oo|
+----[SHA256]-----+

The -t flag sets the encryption algorithm to ed25519. It was prompted to enter a passphrase. Replace your_email@example.com with your GitHub account email. The -C flag adds a comment or label to identify the key, and using an email address is common.

Ed25519 is a public-key signature system and elliptic curve signing algorithm that uses EdDSA and Curve25519.

2. Adding a new SSH key to the GitHub account

To copy the public key to your clipboard, you can do the following:

pbcopy < ~/.ssh/id_ed25519.pub
# Copies the contents of the id_ed25519.pub file to your clipboard

If pbcopy isn't working, you can locate the hidden .ssh folder, open the file in your favorite text editor, and copy it to your clipboard.

Paste the public key into your GitHub settings. You can do this by:

• 1. Opening GitHub and logging in
• 2. Navigating to Settings
• 3. Clicking SSH and GPG keys
• 4. Clicking New SSH key
• 5. Entering a title for the key
• 6. Pasting the key into the Key section
• 7. Clicking Add SSH Key
• 8. Entering your account password if prompted

3. Git Configuration

Install Homebrew if you don't already have it, then:

brew install git

Git configuration settings with the git config command. One of the first things you did was set up your name and email address:

git config --global user.name "Shen Lu"
git config --global user.email shenlu89dev@gmail.com

Check if Git can normally connect with your GitHub account with SSH:

ssh -T -p 443 git@ssh.github.com
The authenticity of host '[ssh.github.com]:443 ([20.205.243.160]:443)' can't be established.
ED25519 key fingerprint is SHA256:+DiY3wvvV6TuJJhbpZisF/zLDA0zPMSvHdkr4UvCOqU.
This host key is known by the following other names/addresses:
    ~/.ssh/known_hosts:1: github.com
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '[ssh.github.com]:443' (ED25519) to the list of known hosts.
Hi shenlu89! You've successfully authenticated, but GitHub does not provide shell access.

Now you can freely use SSH to authenticate Git operations.

Reference

• https://docs.github.com/en/authentication/connecting-to-github-with-ssh/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent
• https://docs.github.com/en/authentication/connecting-to-github-with-ssh/adding-a-new-ssh-key-to-your-github-account
• https://git-scm.com/download/mac