macOS GitHub SSH Certificates Helper

configure-ssh-certs.sh

#!/bin/bash -e

echo "macOS Helper to configure SSH Key to use with GitHub"
echo "based off of instructions reported at:"
echo "https://docs.github.com/en/github/authenticating-to-github/adding-a-new-ssh-key-to-your-github-account"
echo

if [[ "$OSTYPE" != "darwin"* ]]; then
  echo "This script is designed for macOS only..."
  echo "exiting"
  exit 1
fi

echo "Checking existing ed25519 SSH key..."

if [ ! -f "$HOME/.ssh/id_ed25519" ]; then
  echo "You don't have it, generating it for you..."
  echo
  EMAIL=$(git config --global user.email)
  echo "Detected email from git config: $EMAIL"
  echo
  echo "IF IT'S NOT CORRECT, PLEASE HIT CONTROL + C TO EXIT THIS SCRIPT"
  echo "AND PROPERLY CONFIGURE YOUR GIT EMAIL WITH THIS COMMAND:"
  echo "git config --global user.email \"youremail@provider.com\""
  echo
  echo "When prompted where to save the certificate, press ENTER"
  echo "and then press ENTER two more times when asked to put in a password"
  echo
  ssh-keygen -t ed25519 -C "$EMAIL" || true
else
  echo "Good! You have it!"
fi

echo
echo "Starting SSH Agent in the background"
eval "$(ssh-agent -s)"

if [ ! -f "$HOME/.ssh/config" ]; then
  echo
  echo "Creating new SSH config"
  touch "$HOME/.ssh/config"
else
  echo "Using existing SSH config"
fi

if grep -q "IdentityFile ~/.ssh/id_ed25519" "$HOME/.ssh/config"; then
    echo "SSH Config already correct!"
else
  echo "Adding the configuration to SSH Config"

  echo "Host *" >> "$HOME/.ssh/config"
  echo "  AddKeysToAgent yes" >> "$HOME/.ssh/config"
  echo "  IdentityFile ~/.ssh/id_ed25519" >> "$HOME/.ssh/config"
  echo
  echo "Adding private key to SSH Agent"
  ssh-add "$HOME/.ssh/id_ed25519"
fi

echo "Copying SSH public key in the clipboard"
pbcopy < "$HOME/.ssh/id_ed25519.pub"

echo
echo "Now navigate to https://github.com/settings/keys"
echo "and press on New SSH Key"
echo
echo "1. Assign a custom title. For example: macOS SSH Key"
echo "2. and then press COMMAND + V in the Key field"
echo "3. Hit Add SSH Key"
echo "4. Confirm with your password and then enable SSO if needed with your organization"

To run this script, copy, paste and run in your macOS terminal:

curl https://gist.githubusercontent.com/gotev/f4d93e69a30e5a66ef97c8d5d0b350db/raw/eac83fbf8f9b6edcca574871f0631e79b6e80be5/configure-ssh-certs.sh | bash

and then follow instructions on screen.

To clean configuration made by this script:

cd $HOME/.ssh
ssh-add -d "$HOME/.ssh/id_ed25519"
rm -rf config id_ed25519 id_ed25519.pub