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GitHub on Ubuntu

Git and GitHub Setup on Ubuntu 24.04

Initial Question

Human: I have just installed a new Ubuntu 24.04 on my notebook. Please provide me complete instructions on setting up git and GitHub.

Assistant: # Setting Up Git and GitHub on Ubuntu 24.04

Here’s a complete guide to setting up Git and GitHub on your new Ubuntu 24.04 installation:

Install Git

First, let’s install Git via the terminal:

Terminal window
sudo apt update
sudo apt install git

Configure Git

After installation, configure your identity:

Terminal window
git config --global user.name "Marco Antonio Gonzalez Junior"
git config --global user.email "m@rco.sh"
git config --global core.editor "vim"
git config --global init.defaultBranch main

Make sure to use the same email address as your GitHub account.

Generate SSH Key

Using SSH keys is more secure than password authentication:

Terminal window
ssh-keygen -t ed25519 -C "m@rco.sh"

Press Enter to accept the default file location. You can set a passphrase for additional security.

Start the SSH Agent

Terminal window
eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_ed25519

Add SSH Key to GitHub

Copy your public key to clipboard:

Terminal window
cat ~/.ssh/id_ed25519.pub

Then:

  1. Go to GitHub.com and sign in
  2. Click your profile photo in the upper right corner
  3. Go to Settings
  4. Click “SSH and GPG keys” in the sidebar
  5. Click “New SSH key”
  6. Give your key a descriptive title (e.g., “Ubuntu Notebook”)
  7. Paste your key into the “Key” field
  8. Click “Add SSH key”

Verify Connection

Test your SSH connection:

Terminal window
ssh -T git@github.com

You should receive a confirmation message.

Optional Git Configurations

Set default branch name:

Terminal window
git config --global init.defaultBranch main

Setup a credential helper to cache your password:

Terminal window
git config --global credential.helper cache

Create Your First Repository

  1. Create a new repository on GitHub
  2. Clone it to your local machine:
    Terminal window
    git clone git@github.com:yourusername/your-repo-name.git

Basic Git Workflow

Here’s a basic workflow:

Terminal window
# Make changes to files
git add .
git commit -m "Descriptive message about changes"
git push origin main

Is there any specific part of Git or GitHub setup you’d like me to elaborate on?

Follow-up Question

Human: Provide instructions to all commits be signed

Assistant: # Setting Up Signed Git Commits

Signing your Git commits adds an extra layer of verification that you are the author of the changes. Here’s how to set up commit signing on your Ubuntu 24.04 system:

1. Generate a GPG Key

First, install the GPG tools if not already present:

Terminal window
sudo apt update
sudo apt install gnupg

Generate a new GPG key:

Terminal window
gpg --full-generate-key

When prompted:

  • Select the key type (RSA and RSA is recommended)
  • Choose a key size (4096 bits is recommended for security)
  • Choose how long the key should be valid (0 = key does not expire)
  • Enter your name and email address (use the same email as your GitHub account)
  • Set a secure passphrase

2. Get Your GPG Key ID

List your GPG keys to find the ID:

Terminal window
gpg --list-secret-keys --keyid-format=long

Look for the line that starts with sec and note the key ID after the / (it’s a hexadecimal string).

3. Configure Git to Use Your GPG Key

Tell Git to use your key for signing:

Terminal window
git config --global user.signingkey YOUR_KEY_ID

Enable automatic signing for all commits:

Terminal window
git config --global commit.gpgsign true

4. Add Your GPG Key to GitHub

Export your public GPG key:

Terminal window
gpg --armor --export YOUR_KEY_ID

This will print your public key to the terminal. Copy it including the begin and end markers.

Then:

  1. Go to GitHub.com and sign in
  2. Click your profile photo → Settings
  3. Go to “SSH and GPG keys”
  4. Click “New GPG key”
  5. Paste your key in the “Key” field
  6. Click “Add GPG key”

To avoid entering your passphrase every time you commit, set up the GPG agent:

Create or edit the GPG agent configuration file:

Terminal window
mkdir -p ~/.gnupg
echo "default-cache-ttl 34560000" >> ~/.gnupg/gpg-agent.conf
echo "max-cache-ttl 34560000" >> ~/.gnupg/gpg-agent.conf

Restart the GPG agent:

Terminal window
gpgconf --kill gpg-agent
gpg-agent --daemon

6. Test a Signed Commit

Create a test commit to verify everything works:

Terminal window
# Make a change to a file
git add .
git commit -m "Test signed commit"
git push

You should see a “Verified” badge next to your commit on GitHub.

Troubleshooting

If you encounter issues with the GPG signing process:

  1. Ensure the GPG key email matches your Git email:

    Terminal window
    git config --global user.email
    gpg --list-keys

  2. For “secret key not available” errors:

    Terminal window
    export GPG_TTY=$(tty)

    Add this line to your ~/.bashrc or ~/.zshrc file for persistence.

  3. For GPG passphrase prompt issues, install pinentry:

    Terminal window
    sudo apt install pinentry-curses
    echo "pinentry-program /usr/bin/pinentry-curses" >> ~/.gnupg/gpg-agent.conf
    gpgconf --kill gpg-agent

Now all your commits will be automatically signed, verifying your identity to others.