Git & GitHub Certification

Understanding Version Control Fundamentals and Git Architecture

Core Concepts of Version Control

• Grasping the necessity of version control in software development and collaboration, understanding how it tracks changes, facilitates collaboration, and enables recovery.
• Distinguishing between Centralized Version Control Systems (CVCS) and Distributed Version Control Systems (DVCS), highlighting the architectural advantages and disadvantages of each.
• Exploring Git's unique approach as a Distributed Version Control System, emphasizing its local repository model and offline capabilities.

Git's Internal Mechanisms

• Deconstructing Git's snapshot-based storage model, contrasting it with delta-based systems and explaining how Git efficiently stores project history.
• Mastering the Git object model: understanding blobs (file contents), trees (directory structure), commits (project states), and tags (specific points in history).
• Learning how SHA-1 hashes ensure data integrity and uniquely identify every object and state within a Git repository.
• Understanding the concept of references (refs) in Git, including branches and tags, and how they point to specific commits.

Mastering Local Git Repository Operations

Setting Up and Initializing Git

• Performing Git installation on various operating systems and configuring global user settings for author identification.
• Initializing new Git repositories (`git init`) and understanding the `.git` directory's structure and contents.

Tracking and Committing Changes

• Navigating the Git workflow: understanding the working directory, the staging area (index), and the local repository.
• Using `git status` to monitor the state of files, identifying untracked, modified, and staged changes.
• Adding changes to the staging area with `git add`, including selective staging of parts of files.
• Creating meaningful commit messages with `git commit`, adhering to best practices for clarity and historical context.
• Amending previous commits with `git commit --amend` to adjust messages or add forgotten changes.
• Inspecting repository history with `git log`, utilizing various options for filtering, formatting, and visualizing commit history (e.g., `git log --oneline`, `git log --graph`).

Undoing Changes and History Management

• Reverting changes in the working directory or staging area with `git restore`.
• Understanding and applying `git revert` to create new commits that undo previous changes, preserving history.
• Differentiating between `git reset --soft`, `git reset --mixed`, and `git reset --hard` for manipulating the commit history and staging area.
• Managing unwanted files and directories effectively using `.gitignore` and its pattern matching rules.

Advanced Branching, Merging, and Rebasing

Branching Strategies and Mechanics

• Comprehending the concept of branches as lightweight, movable pointers to commits, enabling parallel development.
• Creating new branches (`git branch `) and switching between them (`git switch ` or `git checkout `).
• Understanding the `HEAD` pointer and its role in indicating the current branch and commit.
• Deleting branches (`git branch -d`) after they are no longer needed.

Merging Techniques and Conflict Resolution

• Executing different merge strategies: understanding fast-forward merges when linear history allows.
• Performing three-way merges when commit histories diverge, resulting in a new merge commit.
• Systematically resolving complex merge conflicts, manually editing files, and marking them as resolved.
• Utilizing merge tools to assist in conflict resolution.

Rebasing for Cleaner History

• Understanding the concept of rebasing as rewriting history by moving or combining a sequence of commits to a new base commit.
• Performing interactive rebase (`git rebase -i`) to squash, reword, edit, or drop commits, cleaning up commit history before sharing.
• Applying `git rebase` to integrate changes from one branch onto another without creating a merge commit.
• Recognizing the crucial rule: never rebase public history to avoid disrupting collaborators' repositories.

Collaborating with Remote Repositories and GitHub

Remote Repository Management

• Defining and managing remote repositories with `git remote`, including adding, removing, and renaming remotes.
• Cloning existing repositories from a remote source (`git clone`).
• Fetching changes from a remote repository without integrating them immediately (`git fetch`).
• Pulling changes from a remote repository, understanding it as a `git fetch` followed by a `git merge` or `git rebase`.
• Pushing local changes to a remote repository (`git push`), understanding potential issues like non-fast-forward updates and the use of `git push --force`.

GitHub Platform Mastery

• Setting up a GitHub account and configuring SSH keys for secure authentication with remote repositories.
• Creating new repositories on GitHub and linking them to local Git projects.
• Understanding the typical workflow for contributing to open-source or team projects using the fork-and-clone model.
• Exploring GitHub's interface for repository navigation, file viewing, and history inspection.

Advanced Git Functionality and Utilities

Stashing and Tagging

• Temporarily saving uncommitted changes with `git stash` to switch context without committing.
• Applying, listing, dropping, and clearing stashed changes.
• Creating both lightweight and annotated tags with `git tag` to mark specific points in history, typically for releases.
• Pushing tags to remote repositories.

Targeted Commit Manipulation

• Using `git cherry-pick` to selectively apply individual commits from one branch to another.
• Understanding the implications and use cases for cherry-picking.

Debugging with Git

• Employing `git bisect` to efficiently find the commit that introduced a bug by performing a binary search on the commit history.

Customizing Git Behavior

• Understanding client-side Git hooks (e.g., `pre-commit`, `post-commit`) and how to use them to automate tasks or enforce policies.

Recovering Lost Work

• Utilizing `git reflog` to inspect the history of `HEAD` and branches, enabling recovery of commits that might seem lost.

Managing External Dependencies

• Working with Git submodules to incorporate and manage external repositories within a parent repository.

Effective GitHub Collaboration Workflows

Pull Request Management

• Initiating and managing Pull Requests (PRs) on GitHub to propose changes from a feature branch to a main branch.
• Conducting thorough code reviews within GitHub PRs, providing feedback and requesting changes.
• Understanding various PR merging options: standard merge commit, squash and merge (to combine all PR commits into one), and rebase and merge (to replay commits on top of the target branch).
• Configuring and understanding branch protection rules on GitHub to enforce quality gates (e.g., required reviews, CI/CD checks).

Project Management and Automation

• Leveraging GitHub Issues for bug tracking, feature requests, and task management.
• Utilizing GitHub Projects for kanban-style project tracking and workflow visualization.
• Implementing basic Continuous Integration/Continuous Deployment (CI/CD) pipelines using GitHub Actions, understanding workflow syntax, events, and jobs.
• Exploring GitHub Organizations for managing teams, repositories, and access permissions.
• Deploying static websites directly from a GitHub repository using GitHub Pages.

Git Best Practices and Troubleshooting

Cultivating Best Practices

• Adopting conventional commit message standards for clear, searchable, and automatable commit history.
• Evaluating and selecting appropriate branching strategies for different project sizes and team structures (e.g., Git Flow, GitHub Flow, GitLab Flow).
• Implementing strategies for managing large repositories and optimizing Git performance.

Diagnosing and Resolving Issues

• Troubleshooting common Git errors, including detached HEAD states, persistent merge conflicts, and push/pull failures.
• Understanding and resolving issues related to corrupted repositories or incorrect configurations.

Security Considerations

• Understanding security best practices in Git and GitHub, including managing sensitive information, using SSH keys, and avoiding committing credentials.