DEV Community: Kaviyarasu S

🚀 Getting Started with Docker: A Beginner's Guide

Kaviyarasu S — Mon, 28 Apr 2025 16:00:26 +0000

Docker is a powerful tool that simplifies application deployment by using containers. This guide will walk you through the basics of Docker, from installation to pushing your first image to Docker Hub.

🐳 What is Docker?

Docker is an open-source platform that automates the deployment of applications inside lightweight, portable containers. Containers package an application with all its dependencies, ensuring consistency across multiple environments.

🔧 Prerequisites:

Before we begin, ensure you have the following installed:

Docker Desktop: Download and install from Docker's official website.

**Git: **Install Git from here.

Switch to the Main Branch

If you're working in a different branch and want to return to the main branch:

--git branch
--git checkout main

This moves you back to the main branch where your production code usually lives.

Check the Status of Your Repository

To see what's happening in your Git project (like new files, modified files, etc.):

--git status

It’s a good habit to run git status often, so you know exactly what’s staged, what’s modified, and what’s untracked!

Creating a New Branch Directly from GitHub

Sometimes, you don't even need Git commands.

You can create a new branch directly in the GitHub website:

Here's how:

Go to your repository on GitHub.
Click the branch selector dropdown (usually says main).
In the text box, type the name of your new branch.
Press Enter — GitHub will automatically create the branch for you!

Now, let's get into some basic Docker commands.

Docker helps you containerize your application, making it easier to run anywhere.

1. Check the Docker Version

First, check if Docker is installed and running:

--docker --version

This will show you the installed Docker version.

2. Create a Dockerfile

A Dockerfile is a simple text file with instructions on how to build a Docker image.

Steps:

Create a file named Dockerfile (no extension) in your project folder.

Add simple content inside it, like:

Use an official base image:
FROM node:20

Set working directory:
WORKDIR /app

Copy all files:
COPY . .

Install dependencies:
RUN npm install

Start the application:
CMD ["npm", "start"]

The Dockerfile tells Docker how to set up your application inside a container.

3. Build a Docker Image

After you create your Dockerfile, you can build your Docker image:

--docker build -t your-image-name .
--docker build -t my-first-app .

4. List Available Docker Images

To see all the Docker images on your machine:

--docker images

This shows the repository name, tag, image ID, creation time, and size.

5. Push a Docker Image to a Registry (like Docker Hub)

After building your image, you might want to share it by pushing it to a remote repository like Docker Hub.

First, login:

--docker login

Then tag your image (if needed):

--docker tag your-image-name your-dockerhub-username/your-image-name

Finally, push the image:

--docker push your-dockerhub-username/your-image-name

Git and Docker are essential tools for developers today.
By learning simple commands like checking out branches, checking status, building Dockerfiles, and pushing images, you're setting yourself up for success! 💪

Start small, practice often, and soon you’ll be managing full development workflows like a pro!

Mastering Advanced Git Commands

Kaviyarasu S — Fri, 25 Apr 2025 19:12:45 +0000

Git is a powerful tool, and knowing some advanced commands can really level up your version control game. In this post, we'll go through some commonly used Git commands along with their purpose, how to use them.

1. git diff

Purpose: Show differences between two commits or working directory and index.

Command: git diff

2. git log

Purpose: Show commit history.

Command: git log

3. git clone

Purpose: Clone a remote repository to your system.

Command: git clone https://github.com/Kavi-26/24MCR054

4. git pull

Purpose: Pull changes from remote to local repo.

Command: git pull origin main

5. git push

Purpose: Push local commits to remote.

Command: git push origin main

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6. git blame

Purpose: Show who last modified each line of a file.

Command: git blame ML.txt

7. git merge conflict (not a command)

Note: Conflict occurs during a git merge.

Here’s how to simulate:

git checkout -b new-branch

git checkout main

git merge new-branch

8. git branch

Purpose: List, create, or delete branches.

Command: git branch

9. git checkout -b

Purpose: Create and switch to a new branch.

Command: git checkout –b advanced-git-commands

10 .gitignore

Purpose: File to specify untracked files to ignore.

Steps:

Create .gitignore file in root directory.
Add file patterns to ignore.

e.g.:

*.log
node_modules/

No command needed, Git automatically ignores the specified files.

Github Repository:

Github link: https://github.com/Kavi-26/24MCR054

Create a Local Git Repository

Kaviyarasu S — Wed, 23 Apr 2025 19:24:10 +0000

Initialize a Git repository:

git init

Creates a new Git repository in the folder 24MCR054.

Add a file to staging area:

git add 24MCR054.txt

Adds 24MCR054.txt to the staging area.

Commit the file:

git commit -m "Added Personal Details"

Creates a commit with the message "Added Personal Details".

Check Git status:

 git status

Shows that 24MCR054.txt has been modified but not staged.

View commit log:

 git log

Displays the commit history (one commit at this point).

Add remote GitHub repository:

 git remote add origin https://github.com/Kavi-26/24MCR054.git

Links the local repository to a remote GitHub repo.

Check current branch:

 git branch

Shows the current branch is main.

Rename branch from master to main:

 git branch -M main

Renames the current branch to main.

Set Git global config for email:

git config --global user.email "26kaviyarasu2002@gmail.com"

Sets your global Git identity.

Push code to remote repo for the first time:

 git push -u origin main

Pushes the main branch to GitHub and sets upstream tracking.

Then , Again We will Modify or add new file means we need to follow the same steps, like

git add .
git commit -m “message”
git push origin main

Github Repository:

Github link: https://github.com/Kavi-26/24MCR054