Git Basics and Essential Commands
What is Git ?
Git is the tool that helps you to manage changes in you code. It helps you to keep track of every little changes to file. you can always look back at previous versions or undo mistakes if needed. Every developer gets a full copy of the project, including its history, on their own machine. This means you can work offline, experiment freely, and still keep everything organized.
Why Git is Used ?
Git is used because this solve many problems of the developers :
Collaboration → Multiple people work on same file at same time without over write each other code.
It keep full history of the code what changes are we made in our code
It make team work easy and manageable
Allow Experimenting without make any change in main code
It helps to fix mistakes by role back changes.
Git Basics and Core Terminologies
Git basics : Basics steps of the Git.
Repository (Repo) : A repository is a project folder that Git tracks. It contains your code and the entire change history.
Commit : A commit is a snapshot of your code at a specific point in time. Each commit has a message explaining what changed.
Branch : A branch is an independent line of development. You can create branches to add features or fix bugs without touching the main code.
HEAD : HEAD is a pointer that tells Git which commit or branch you are currently working on.
Core Terminologies
Git Workflow (Very Important)
Git works in three main stages:
Working Directory
This is your normal project folder on your laptop.
You create files, edit code, delete things, rename files.
Git is watching, but nothing is saved yet.
Files here can be:
Untracked: Git has never seen them before.
Modified: Git knows the file, but you changed it.
Example:
You open main.py and add a new function.
At this point, the change exists only on your machine. If your system crashes, Git has nothing saved.
Staging Area (Index)
This is the most important and most misunderstood part.
The staging area is like a preview of the next commit.
You choose exactly which changes should be saved.
Nothing is permanent yet.
Repository (Commit History)
This is where Git permanently stores changes.
When you commit:
Git takes everything from the staging area
Saves it as a snapshot
Assigns it a unique commit ID
Adds your message describing what changed
A simple real-life Example:
Working Directory: Writing rough notes
Staging Area: Highlighting what goes into the final answer
Repository: Submitting the exam paper
Common Git Commands
Initialize a Repository :
git init
Creat new git repositort in the current folder.
Check Repository Status :
git status
Shows modified files, staged files, and what Git is tracking.
Add Files to Staging Area :
git add filename
or
git add .
Stages one file or all changes.
Commit Changes :
git commit -m "Your message here"
Saves staged changes with a clear message.
View Commit History
git log
Shows all previous commits in order.
git diff
git diff shows what has changed in your files.
It compares different versions of your code and highlights the exact lines added, removed, or modified.
git diff
Shows changes in the working directory that are not yet staged.
What you’ll see:
Lines starting with
-were removedLines starting with
+were added
git add <file_name>
git add tells Git which changes you want to include in the next commit.
It moves files from the working directory to the staging area.
Basic usage
git add index.html
Stages only index.html.
git revert
git revert is the safe way to undo a commit.
It does not delete history. Instead, it creates a new commit that reverses the changes of an earlier one.
git revert <commit-hash>
git reset
git reset moves HEAD backward to a previous commit.
Unlike revert, it can rewrite history, so it must be used carefully.
There are three common modes.
1. Soft reset
git reset --soft <commit-hash>
Keeps changes staged
Moves HEAD only
Used when you want to fix a commit message or regroup commits.
2. Mixed reset (default)
git reset <commit-hash>
Keeps changes in files
Unstages them
Used when you added files by mistake.
3. Hard reset
git reset --hard <commit-hash>
Deletes commits
Deletes file changes
Very dangerous.
