Git - A Beginner's Guide

What is Git?

Git is a Version Control System. It tracks every change we make to our files. If we mess up, we can go back to a previous version instantly. It allows us to work together on the same project without deleting each other's work.

Usages

• Revert Changes: If we make any mistake or want to go back to a previous stage of our development, we can revert back.

• Collaboration: We can have 10 people working on the same project at the same time on separate branches.

• Feature Testing: We can test a new idea in a separate branch without breaking our main working app.

• Backup: Pushing our code to Global Repository (GitHub/GitLab) saves it in the cloud.

Git Workflow

1. The Working Directory

   • Represents the current state of the files on our local filesystem.

   • This is where we actively write code, refactor functions, and modify assets.

   • Changes here are either Modified (changed but known to Git) or Untracked (new files Git has never seen).

2. The Staging Area (The Index)

   • The Staging Area acts as a buffer between our working files and the permanent repository.

   • It allows us to draft our next commit. We might have modified ten files, but we only want to include three of them in a specific update.

   • When we run git add, we are updating the Index.

3. The Local Repository (HEAD)

   • This is the hidden .git directory inside our project root which serves as our personal database of the project's history.

   • When we run git commit, we record a permanent snapshot of the Staging Area into this database.

   • The latest commit in our current branch is referred to as HEAD.

4. The Remote Repository (Upstream)

   • This is the copy of the repository hosted on a remote server (e.g., GitHub, GitLab).

   • We synchronize our Local Repository with the Remote Repository using push (upload) and pull (download) commands.

   • It provides redundancy (backup) and facilitates collaboration.

   • Our local changes remain private until we explicitly push them to the remote, allowing us to work offline or draft feature branches without affecting the team's production code.

Git Commands - Cheat Sheet

1. Setup

• git config --global user.name "Our Name" — We tell Git who we are.

• git config --global user.email "email@example.com" — We tell Git our email.

2. Starting a Project

• git init — We turn our current folder into a Git repository.

• git clone <url> — We download an existing project from the internet.

3. Save & Sync

• git status — Shows us which files are changed or staged.

• git add . — We move all changed files to the Staging Area.

• git add <file> — We move just one specific file to the Staging Area.

• git commit -m "message" — We save the staged files permanently.

• git push — We upload our commits to the cloud (GitHub/GitLab).

• git pull — We download new changes from the cloud to our computer.

4. Branching

• git branch — Lists all our branches.

• git branch <name> — We create a new branch.

• git checkout <name> — We switch to a branch.

• git checkout -b <name> — We create and switch to a new branch.

• git merge <name> — We combine the specified branch into our current one.

5. Auditing

• git log — Shows a list of all our past commits (history).

• git reset HEAD~1 — We undo the last commit (but keep our changes).

• git stash — We temporarily hide our changes to work on something else.

• git stash pop — We bring back the hidden changes.