Git Knowledge Base
A comprehensive reference for everything Git β 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 β including its complete history β 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.
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 β 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 β usually a release marker |
The Three Trees
Understanding Git's three trees is the key to understanding almost every Git command:
π΄Git Trees: STAGE
Staging Area (Index)
Syntax: git add <file>
Description: Prepares local working changes to be recorded in the next history commit.
- Internal Mechanics:
- Moves your changes from the Working Tree (local disk) to the Staging Area.
- Computes file content SHA-1 hashes and creates blob objects in Git's index database.
- Allows selective chunk/hunk commits using command flags like git add -p.
π‘ Use the tabs above to trigger file flows between Working Tree, Index/Stage, and Repository states.
git addmoves changes from the working tree into the indexgit commitmoves changes from the index into the repositorygit checkout/git restoremoves changes from the repository or index back into the working tree
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 |
How to Use This Documentation
Use the sidebar to navigate by topic area:
- Basics β
add,commit,push,fetch/pull,status/diff - Branching β creating branches, merging, rebasing, conflict resolution
- History & Rewriting β
cherry-pick,squash,fixup,reset,revert,reflog - Collaboration β remotes, tags, stash, submodules
- Advanced β hooks, aliases,
bisect, worktrees - Workflows β Git Flow, trunk-based development, conventional commits, PR best practices
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.