OGG… How can I set up ssh connection to GitHub repository?

ssh
Author

Ryo Nakagami

Published

2024-12-17

Modified

2024-12-17

Problem

  • I want to set up an SSH connection for a GitHub repository with my macOS

Solution

▶  Steps

  1. Generate a new ssh key
  2. Add the SSH Key to the SSH Agent
  3. Register the public key to GitHub
  4. test ssh connection
  5. update the ssh config file

▶  Setup

1. Generate a new ssh key
ssh-keygen -t ed25519 -C "hoshinokirby@gmail.com" -f ~/.ssh/kirby_github_key

Option -t specifies the type of key to generate. ed25519 is faster and more secure than older algorithms like RSA and produces shorter keys while maintaining strong security.

Option -C adds a comment to the key for identification purposes.

-f specifies the filename and location for the generated key pair. This will generate two files

  • kirby_github_key: The private key (keep this secure! do not share!).
  • kirby_github_key.pub: The public key (you upload this to GitHub).
2. Add the SSH Key to the SSH Agent
eval "$(ssh-agent -s)"
ssh-add ./.ssh/kirby_github_key

The ssh-add command adds your private SSH key to the SSH authentication agent (ssh-agent) so it can be used for SSH connections without repeatedly asking for the key’s passphrase. If the key (kirby_github_key) isn’t added to ssh-agent, SSH won’t know to use it. You might encounter the error like this;

Permission denied (publickey).
3. Register the public key to GitHub
cat ~/.ssh/kirby_github_key.pub

After opening the file, copy the strings and register it at the Github at Settings > SSH and GPG keys > New SSH key

Then, test your connection by

4. test ssh connection
$ ssh -T git@github.com

if connection established successfully, the following message will pop up

Enter passphrase for key '/Users/hosinokkirby/.ssh/kirby_github_key': 
Hi Kirby! You've successfully authenticated, but GitHub does not provide shell access.

▶  Update the ssh config file

Running ssh-add munally evewrytime will be troublesome. To avoid it, you can configure SSH to use the key automatically by editing your ~/.ssh/config file:

~/.ssh/config
Host github github.com
  HostName github.com
  User git
  Port 22
  IdentityFile ~/.ssh/kirby_github_key
  IdentitiesOnly yes
  TCPKeepAlive yes