Git¶

A comprehensive course on Git - from your first commit through the internals of the object model, collaboration workflows across platforms, and advanced operations at scale. These guides take you from "I know I should use version control" to understanding Git deeply enough to debug, optimize, and architect workflows around it.

Each guide is self-contained, but the order below follows a natural learning path.

Foundations¶

Introduction: Why Git, and Why Version Control ¶

The history of version control from RCS through SVN to distributed systems, and why Linus Torvalds built Git for the Linux kernel. Covers installing Git on every platform, first-time configuration, and a mental model preview of Git as a content-addressable filesystem.

The Three Trees: Working Directory, Index, and Repository ¶

Git's core mental model - the working tree, staging area, and committed history. Covers the complete file lifecycle from untracked through committed, the .gitignore pattern syntax, and a first look inside the .git directory.

Commits and History ¶

What a commit actually stores and how to explore history. Covers commit object anatomy, writing effective messages, git log formatting and filtering in depth, git diff across the three trees, and amending commits.

Branches and Merging ¶

Branches as movable pointers, not copies. Covers creating, switching, and managing branches, fast-forward vs three-way merges, conflict resolution strategies, and the difference between git switch and git checkout.

Core Workflows¶

Remote Repositories ¶

Working with code that lives somewhere else. Covers clone, fetch vs pull, push and rejection handling, tracking branches, multiple remotes for fork workflows, and SSH vs HTTPS authentication setup.

Rewriting History ¶

When and how to clean up your commit history. Covers commit --amend, interactive rebase (squash, fixup, reorder, edit), cherry-pick, revert vs reset with all three modes, and the reflog as your safety net.

Stashing and the Worktree ¶

Interrupting work without losing it. Covers git stash in depth (push, pop, apply, branch), stashing untracked and ignored files, multiple working trees with git worktree, and git clean for resetting your workspace.

Configuring Git ¶

Making Git work the way you want. Covers configuration levels and precedence, aliases, custom diff/merge tools, conditional includes for work vs personal, .gitattributes for line endings and diff drivers, and environment variables.

Git Internals¶

The Object Model ¶

Git as a content-addressable filesystem. Covers the four object types (blobs, trees, commits, annotated tags), SHA-1 hashing, the .git/objects directory, and building a commit entirely with plumbing commands.

Refs, the Reflog, and the DAG ¶

How Git names things and connects them. Covers references, symbolic refs like HEAD, the directed acyclic graph, garbage collection, the reflog's per-ref change history, and how packfiles compress objects with delta encoding.

Transfer Protocols and Plumbing ¶

How fetch and push work at the protocol level. Covers smart HTTP, SSH, and native transports, pack negotiation, shallow and partial clones, sparse checkout, git bundle for offline transfer, and protocol v2 improvements.

Platform Collaboration¶

Collaboration Workflows ¶

Choosing how your team works with Git. Covers centralized, feature branch, Gitflow, trunk-based, and forking workflows, plus pull request best practices, branch protection, and release management with semantic versioning.

GitHub, GitLab, and Bitbucket ¶

Platform-specific features and tooling. Covers PRs vs MRs, CI/CD configuration (Actions, .gitlab-ci.yml, Pipelines), gh and glab CLIs, code owners, and migrating between platforms.