Git Knowledge Base

A comprehensive reference for everything Git — from staging your first file to rewriting history, managing complex merges, and running team-wide workflows.

What is Git?

Git is a distributed version control system (VCS) created by Linus Torvalds in 2005. Every developer has a full copy of the repository — including its complete history — on their local machine. This means most operations are instant, offline-capable, and non-destructive.

Git tracks changes as a directed acyclic graph (DAG) of commits, where each commit is an immutable snapshot of the entire project tree at a point in time (not a diff). Branches are simply lightweight, movable pointers to commits.

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Core Concepts at a Glance

Concept	What it is
Repository	The .git directory containing all history, objects, and refs
Working Tree	Your actual files on disk — what you edit
Index / Staging Area	The preparation zone between working tree and commits
Commit	An immutable snapshot of the staged tree plus metadata
Branch	A movable pointer to a commit (refs/heads/name)
HEAD	A pointer to the currently checked-out commit or branch
Remote	A named URL to another repository (e.g., origin)
Tag	An immutable pointer to a commit — usually a release marker

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The Three Trees

Understanding Git's three trees is the key to understanding almost every Git command:

Working Tree    →  git add  →   Index (Stage)   →  git commit  →   Repository
(your files)                   (snapshot draft)                    (commit history)
      ↑                                                                   |
      └─────────────────── git checkout / git restore ──────────────────┘

• git add moves changes from the working tree into the index
• git commit moves changes from the index into the repository
• git checkout / git restore moves changes from the repository or index back into the working tree

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Quick Command Reference

Task	Command
Stage all changes	git add .
Commit with message	git commit -m "feat: description"
Push to remote	git push origin branch-name
Pull latest changes	git pull --rebase origin main
Create and switch branch	git switch -c feature/my-feature
Merge a branch	git merge --no-ff feature/my-feature
Rebase onto main	git rebase main
Interactive rebase	git rebase -i HEAD~5
Cherry-pick a commit	git cherry-pick <sha>
Squash last N commits	git rebase -i HEAD~N
Stash work-in-progress	git stash push -m "wip: description"
Reset to previous commit	git reset --soft HEAD~1
Undo a commit safely	git revert <sha>
Find which commit introduced a bug	git bisect start
View full history graph	git log --oneline --graph --all

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How to Use This Documentation

Use the sidebar to navigate by topic area:

• Basics — add, commit, push, fetch/pull, status/diff
• Branching — creating branches, merging, rebasing, conflict resolution
• History & Rewriting — cherry-pick, squash, fixup, reset, revert, reflog
• Collaboration — remotes, tags, stash, submodules
• Advanced — hooks, aliases, bisect, worktrees
• Workflows — Git Flow, trunk-based development, conventional commits, PR best practices

Golden Rule of Git

Never rewrite history on shared branches. Rebase, squash, and fixup are safe on your own feature branches. Once a branch is pushed and shared with others, use git revert instead.