Beginner Guide for Git& git-hub

Biswajit Das — Fri, 07 Mar 2025 02:34:19 +0000

What is a git?

Git is version control software, which is used to keep track changes on software files.

REPO➖

It store multiple software files in a single folder.

All used Commands

Basic Command

git version → used for check git version

git status → it shows which folders are tracked or untracked.

Project command

git init → used only for one time in a project.

git add → used for add file in current branch.

git commit -m "add your message" → It is worked like check points and used for comment in a pash.

git push origin main → it push git history on the git hun.

git follow atomic commits. Means keep commit on an one feature or one component at a time.
Commit must be order from. e.g.: Add navbar
commit works:
- commit are depends on their parent commit.
- Each commits has their own hash code.

Git configure commands

git config --global [user.](http://user.name)email → this command configure your email address for globally. if you want to store your email for local project then use --local instead of global.

git config --global user.username → it also did some thing.

git log --oneline → to see all commits in the current branch.

.gitignore → it is file. That is untracked by git. we can put file name which are private.

Git Branch and Conflict

What is Branch ?
- Branch in git is known as a timeline. Different programmer can worked different timeline in same Repos. like some worked on hero section in a website and other one worked on Navbar. main is root branch.

git branch → it is used to create new branch.

git switch → it is used for switching different branches.

we can replace switch with checkout . it did same work.
Head always point Main branch, where is current at.

If we not mange other branches, then one work in one branch is vanished from other branch. like Dr. strange

git branch → used to see all branch.

Green one is current branch where we staying.

Git Merge Different branch/timeline

To merge different timeline with main. we must comes first on main branch. then type this command:

git merge <add_branchname_that_will_be_merge> → use to marge .

❗ sometimes conflicts happens when both programmer write code in same file.
To mange conflicts we have three choice: 1. Accept both code. 2. Accept incoming code. 3. Accept main branch code.
This process can be done by manually.

Git diff and stash

git diff used for compare same file with current commit and previous commit.
--- and +++ indicates changes in file, not deletion and insertion.
git stash is special command on git. for storing changes in temporary. don’t need add and commit before changing branches.
we can back our changes in any branches using this command.
git stash pop → used back stashed worked.
git restore → it works same.

Rebase

Rebase is an alternative of merge and a cleaning tool. It is used for marge two different timeline into a single timeline.

❗ don’t run this command when you are on main branch. because it will change your commit history.

git rebase <branch_name>

GITHUB

Git is a version control and git-hub is a service to host git online.

git work with SSH key, which is very sensitive. for more go git-hub doc.

Add Git into Github.

git remote add origin <url> - connect git with git-hub repo.

git remote -v → check git-hub repo is configured or not.

git push -u origin main → used to send code base into the main branch in git-hub. -u set upstream that allow us for future command git push

Disclaimer.

when clone some repos, you just get main branch, rest of repos are not configured with main branch.

OOPs concepts 💖

Biswajit Das — Sat, 30 Nov 2024 14:12:37 +0000

Object

⇒ An Object is a fundamental unit of Object-Oriented Programming (OOP) that represents real-world entities. It is created from a class and contains the attributes and behaviors defined by the class. Once an object is created, it can execute the methods and access the properties of its class.

Class

⇒ A Class is a blueprint for objects. It represents a collection of objects and defines their properties and behaviors. Classes do not take up memory space until an object is created from them.

A class can be considered as a logical entity that encapsulates data and methods.
Class names typically start with a capital letter.

Example: A class defines the common properties and methods shared by all objects of the same type.

Access Modifiers

In Java, access modifiers control the scope and visibility of classes, methods, and variables. They provide security and define accessibility.

Types of Access Modifiers:

Default:
- If no access modifier is specified, Java treats the variable, method, or class as having the default modifier.
- Default modifiers are accessible only within the same package. Example:
- Two code files in the same package can access default methods or variables simply by creating an object of the file containing the methods.
Private:
- Specified using the private keyword.
- Accessible only within the class in which they are declared.
- Private modifiers cannot be used on top-level classes or interfaces because they limit access to within the enclosing class.

Example: Private modifiers are typically used for nested classes or data members within a top-level class. Private members can only be accessed using getter and setter methods.

Protected:
- Declared with the protected keyword.
- Accessible within the same package or in subclasses in different packages.
- Not accessible in unrelated classes outside the package.
Public:
- Specified with the public keyword.
- Accessible from any class, package, or subclass, even outside the package.

Keyword `this`

⇒ The this keyword refers to the current object. It is used to access the object’s variables or reference the object itself within a method or constructor.

OOP Principles

Object-Oriented Programming (OOP) revolves around four main concepts:

Encapsulation:
- Encapsulation is the process of wrapping up data and methods in a single unit.
- It promotes data hiding by restricting access to certain components.
- Example: A class acts as a capsule that holds data (attributes) and methods (behaviors).
Polymorphism: Enables methods or objects to perform different tasks based on their implementation.
Abstraction: Focuses on exposing only the essential features of an object while hiding the implementation details.
Inheritance: Allows one class to inherit the properties and methods of another class, promoting code reuse.

Constructors

A constructor is a special type of method in a class:

It is invoked automatically when an object is created.
It is used to initialize the properties of an object.
Constructors share the same name as the class and do not have a return type.

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