Git from Zero to Functional

Learn about Git versioning tool + GitHub integration.

• version
• git
• bash
• productivity
• code versions

Git from Zero to Functional: A Guide for Entry & Junior Developers (2024)

Table of Contents

1. Introduction to Git and GitHub
2. Setting Up Git
3. Basic Git Commands
4. Collaborating on GitHub
5. Branching and Merging
6. Resolving Conflicts
7. Pull Requests and Code Reviews
8. Setting Up SSH for GitHub
9. App Authorizations on GitHub
10. Creating a Personal Access Token
11. Best Practices
12. Common Pitfalls
13. Conclusion

1. Introduction to Git and GitHub

What is Git?

Git is a version control system (VCS) designed to manage and track changes to code over time. It allows multiple people to collaborate on a project, manage different versions, and keep a history of changes.

What is GitHub?

GitHub is a web-based platform that hosts Git repositories and provides tools for collaboration, like issue tracking, pull requests, and code reviews.

Why Use Git and GitHub?

• Track Changes: You can revert to previous versions easily.
• Collaborate: Multiple people can work on the same project simultaneously.
• Backup: Keeps a remote copy of your project that can be accessed anywhere.

2. Setting Up Git

Installing Git

1. Windows:

   • Download the Git installer from git-scm.com.
   • Follow the setup instructions.

2. macOS:

   • Install via Homebrew:

     brew install git
     

3. Linux:

   • Install via your package manager (Debian/Ubuntu):

     sudo apt install git
     

Configuring Git

After installing, configure Git with your user information:

git config --global user.name "Your Name"
git config --global user.email "[email protected]"

You can check your configuration with:

git config --list

3. Basic Git Commands

Initialize a Repository

Create a new Git repository in your project folder:

git init

Cloning a Repository

To clone an existing GitHub repository:

git clone https://github.com/username/repo-name.git

Checking Repository Status

See which files have changed:

git status

Staging and Committing Changes

1. Stage files (prepare them for commit):

   git add <filename>   # To add specific files
   git add .            # To add all changes
   

2. Commit your changes (save the changes to history):

   git commit -m "Describe your changes"
   

Viewing Commit History

View a list of commits:

git log

4. Collaborating on GitHub

Pushing Changes to GitHub

After committing, push changes to your GitHub repository:

git push origin main  # or master depending on the branch

Pulling Changes from GitHub

Get the latest changes from the remote repository:

git pull origin main

5. Branching and Merging

Creating and Switching Branches

Branches allow you to work on different features or bug fixes without affecting the main project. To create a new branch:

git checkout -b feature-branch-name

Switch between branches:

git checkout main

Merging Branches

To merge your branch into main, first switch to main:

git checkout main
git merge feature-branch-name

6. Resolving Conflicts

When multiple people make changes to the same file, Git may encounter conflicts. Conflicts need to be resolved manually:

1. Open the file with the conflict.
2. Edit the conflicting sections marked by Git.
3. After resolving, stage and commit the changes:

   git add conflicted-file
   git commit -m "Resolved conflict"
   

7. Pull Requests and Code Reviews

A Pull Request (PR) is a request to merge changes from one branch into another (usually from your branch into main).

1. Push your branch to GitHub:

   git push origin feature-branch-name
   

2. Create a pull request on GitHub:

   • Go to the repository on GitHub.
   • Click Pull Requests > New Pull Request.
   • Select the branch and submit your PR.

Code Reviews

Before merging, other developers can review your code. They might suggest changes, which can be made by updating your branch and pushing the changes.

8. Setting Up SSH for GitHub

Why Use SSH?

Using SSH allows you to securely interact with your GitHub repository without needing to enter your password every time you push or pull changes.

Generating an SSH Key

1. Generate a new SSH key:

   ssh-keygen -t ed25519 -C "[email protected]"
   

   When prompted, press Enter to accept the default location. Optionally, you can set a passphrase for extra security.

2. Start the SSH agent:

   eval "$(ssh-agent -s)"
   

3. Add your SSH key to the agent:

   ssh-add ~/.ssh/id_ed25519
   

4. Copy your SSH key to the clipboard:

   cat ~/.ssh/id_ed25519.pub
   

   Copy the entire output.

Adding Your SSH Key to GitHub

1. Go to GitHub and click on your profile picture, then navigate to Settings.
2. On the left sidebar, click SSH and GPG keys.
3. Click New SSH Key.
4. Paste the SSH key from your clipboard, name it, and click Add SSH Key.

Now, your GitHub account is configured to use SSH for secure communication.

9. App Authorizations on GitHub

GitHub allows third-party applications to access your account to automate workflows or provide additional tools.

Authorizing Applications

1. Go to your GitHub Settings.
2. On the left sidebar, click Applications.
3. Here you will find two tabs: Authorized OAuth Apps and Authorized GitHub Apps.
   • OAuth Apps: These apps authenticate with GitHub via OAuth and might request various permissions.
   • GitHub Apps: Apps installed on specific repositories or the entire GitHub account.

Authorizing a New App

• To authorize a new OAuth app:
  1. You will usually be redirected to GitHub from the app's website.
  2. GitHub will ask for permission to grant the app access to your account.
  3. Review the permissions and click Authorize.

You can always revoke or modify permissions from the same settings page.

10. Creating a Personal Access Token

Why Use a Personal Access Token?

GitHub has deprecated password-based authentication for Git operations, so a Personal Access Token (PAT) is used as a secure alternative for authentication.

Steps to Create a Personal Access Token

1. Go to GitHub:

   • Navigate to your GitHub profile and click on Settings.

2. Access Developer Settings:

   • On the left sidebar, click Developer settings.

3. Generate a New Token:

   • Under Personal Access Tokens, click Tokens (classic), then click Generate new token.

4. Set Token Scopes:

   • Give your token a name and set an expiration date (optional).
   • Select the scopes (permissions) you want to grant the token. For basic repository usage, check:
     • repo: Full control of private repositories.
     • workflow: Write access to actions and workflows.
     • admin:repo_hook: Read/write access to repository hooks.

5. Generate and Store the Token:

   • After selecting the scopes, click Generate token.
   • Important: Copy the token immediately and store it securely (you won’t be able to see it again).

Using the Token for Git

To use your personal access token, you’ll replace your GitHub password with the token when performing Git operations:

git clone https://github.com/username/repo.git

When prompted for your password, use the personal access token instead of your password.

11. Best Practices

• Commit Often: Make small, meaningful commits with clear messages.
• Use Branches: Create a new branch for each feature or bug fix.
• Pull Regularly: Frequently pull changes from the remote repository to avoid conflicts.
• Code Reviews: Always create a pull request and get a code

review before merging to main.

12. Common Pitfalls

• Forgetting to Pull: Always pull the latest changes before starting new work.
• Commit Messages: Avoid vague messages like “fixed stuff.” Be specific about the changes you made.
• Not Using Branches: Directly committing to main can lead to conflicts and unstable code.

13. Conclusion

This guide serves as a starting point for developers who are new to Git. Follow these steps and best practices to confidently manage your projects and collaborate effectively using Git and GitHub.

References

• Git Documentation: https://git-scm.com/doc
• GitHub Documentation: https://docs.github.com