Forem: Dinesh Arumugam

Grasping the mkdir command

Dinesh Arumugam — Tue, 29 Apr 2025 12:50:38 +0000

Tables

Introduction
Overview of mkdir
Hands-On Scenarios and Lessons Learned
Mistakes to Avoid
Quick Summary

Introduction

As part of my RHCSA + RHCE Fast-Track Training with the Cloud Whistler community, I’m continuing to document everything I learn—this time from Day 4 of my 30-day Linux challenge.

In this post, I’ve shared the importance of mkdir command for structuring wise files and projects folders.

Overview of mkdir

What is mkdir?
mkdir stands for make directory. It's used to create new folders (directories) in your Linux file system.

Hands-On Scenarios and Lessons Learned

🛠️ Hands-On Scenarios and Lessons Learned
Creating a single folder in the top level directly /
Mkdir /aws : command to create a folder in top level directory

How to create more than directories
Mkdir /uk /Canada /Australia : command to create a more than one folder directories in top directory

How to create multiple directories
Mkdir /azure{1..5} : command to create a multiple folder directories in top directory

Create a directory inside a directory

Create a Parent directory inside another directory
Mkdir -p /gcp/v1/v2/v3

Mistakes to Avoid

Here are a couple of things that tripped me up early on while using mkdir:
Missing the -p flag for nested folders
If you try to create a folder inside another one that doesn’t exist yet, you’ll get an error like:

mkdir: cannot create directory ‘/path/to/folder’: No such file or directory

Just add the -p flag to tell Linux to create any missing parent folders too:
*mkdir -p /path/to/folder
*
Spaces in folder names without quotes
If your folder name has spaces (like My Folder), Linux thinks you're typing two separate arguments. Wrap it in quotes or escape the space:

mkdir "My Folder"
mkdir My\ Folder

Trust me, these small things can save a lot of time and confusion when you're just getting started!

Quick Summary

mkdir might look simple at first, but once you get the hang of its options, it becomes a powerful tool for staying efficient and organized.A well-structured file system not only makes your life easier down the road

Got a favorite Linux command or a hard lesson learned? I’d love to hear it. Let’s swap stories—connect with me on https://www.linkedin.com/in/dinesharumugam86/#.

🐧 Mastering the Basics: A Beginner’s Guide to the Linux File System Hierarchy

Dinesh Arumugam — Sat, 26 Apr 2025 12:43:44 +0000

Hi everyone!
I'm continuing my 30-day Linux challenge as part of my preparation for the RHCSA certification.
Today, for Day 2, I’m excited to walk you through one of the most important — but often overlooked — topics in Linux: File System Hierarchy. 🧡

If you’re completely new to Linux, or starting your RHCSA journey, understanding how files and directories are organized isn’t just nice to know — it’s absolutely essential.

In this article, I’ll break down:

✅ What the Linux File System Hierarchy really means
✅ How each directory is used practically in real-world IT systems
✅ Easy comparisons with Windows, so anyone — even from a non-technical background — can follow
✅ Real-life IT use cases
✅ Pro tips to remember things faster

Let’s dive in together! ⚡

📁 What Is the Linux File System Hierarchy?
In Linux, everything starts from a single root — /.

Unlike Windows where you have drives like C:\, D:\, and so on, in Linux, there’s just one big family tree, starting from /.

All files, folders, programs, and settings live somewhere underneath /.
Think of it like a giant organised city — where every street (folder) has a specific purpose.

✅ This structure keeps Linux modular, organized, and scalable — especially important in server environments where hundreds of applications and users might exist.

🗂️ Quick Overview of Key Directories (Compared to Windows)

🛠 Simple Command to Explore:

🖥️ This command shows you a list of top-level folders in Linux —
Just like opening "This PC" on Windows and seeing your C:\, D:\ drives!

🔥 Why Understanding This Matters (Especially for RHCSA)

📂 Navigation becomes second nature — You’ll know where to find logs, configs, apps, or user files.
🔍 Troubleshooting becomes faster — No more Googling "where are Linux logs"; you’ll go straight to /var/log.
🧠 You think like a SysAdmin — Certifications and real-world IT jobs expect you to move without a GUI.
🚀 You feel confident in the terminal — No more feeling “lost”!

💡 RHCSA Exam Tips:

Many questions revolve around /home, /etc, /var/log.
Understanding the file system structure helps you solve tasks faster and more confidently.

🧪 Real-World IT Scenarios (You'll Actually Use This!)
✅ Need to find out why your server isn't booting? → Check /boot and /var/log.
✅ Setting up a new Nginx or Apache web server? → Config files live under /etc/.
✅ Creating a new user account? → Their data will be stored under /home/username/.
✅ Installing custom software manually? → It usually goes into /usr/local/bin.
✅ Need to attach a USB drive? → It gets mounted under /mnt or /media.

🧠 Best Practices and Recommendations

💡 Pro Tips for Linux beginners:

Use ls -l / often to map the system in your mind.
Spend 5–10 minutes exploring /etc, /var, /usr, etc.
Don’t just memorize — interact! Real understanding comes from practicing.
Always compare with Windows in your mind — it makes everything click faster!

🔚 Quick Summary

Today’s lesson might seem basic — but this is the backbone of Linux.

By learning what’s where and why, you’ll manage Linux systems with confidence, just like you navigate Windows.
Every great SysAdmin, DevOps engineer, and Linux power user started right here.

I'd love to hear your thoughts! 🧡

Are you also learning Linux?

What tips helped you when you were starting out?

Let’s grow and learn together! 🚀

Feel free to connect with me here on dev.to or LinkedIn!

30DaysLinuxChallenge #LinuxForBeginners #RHCSA #LinuxFileSystem #CloudWhistler #DevOps #LinuxJourney #WindowsVsLinux

How to Install Red Hat Enterprise Linux 9 on VirtualBox on Windows

Dinesh Arumugam — Thu, 24 Apr 2025 19:21:08 +0000

🚀 How to Setup RHEL 9 on Windows Using VirtualBox – Day 1 of My 30-Day Linux Challenge

👋 Introduction
I’ve recently kicked off my 30-day Linux challenge as part of my preparation for the RHCSA exam. This post marks Day 1, where I show you how I set up a Red Hat Enterprise Linux 9 lab on Windows using Oracle VirtualBox—step-by-step.

Whether you’re just getting started with Linux or gearing up for a certification, this setup guide is for you.

Stay tuned—29 more days of Linux adventures ahead!

📋 Requirements
✅ Oracle VirtualBox – https://www.virtualbox.org/
✅ RHEL 9 ISO File (requires a free Red Hat Developer account) – https://developers.redhat.com/products/rhel/download
✅ A machine with at least 4GB RAM

🛠 Step-by-Step Lab Setup in Oracle VirtualBox
Step 1: Create a New Virtual Machine
Open VirtualBox
Go to Machine → New

Step 2: Enter VM Details
Name: RHEL9-VM1
Type: Linux
Version: Red Hat (64-bit)

Step 3: Set Memory Size
Allocate 2GB RAM (2048 MB)

Step 4: Created a Virtual Hard Disk
While in the installation process

Choose VDI (VirtualBox Disk Image)
Select Dynamically allocated
Set size to 25GB
Click Create

Step 5: Adjust VM Settings
Settings → System → Processor
Set processor count to 2

System → Motherboard
Change pointing device to USB Tablet
Click OK to save changes

Step 6: Attach the RHEL 9 ISO
Click Start on the VM
When prompted, click the folder icon to choose a disk

Click the folder icon and select the rhel-baseos-9.0-x86_64-dvd.iso
Click Start

🧑‍💻 Begin Installation
Step 7: Start RHEL Installer
Use arrow keys to select Install Red Hat Enterprise Linux 9. Press Enter

Step 8: Language Selection
Select your preferred language
Click Continue

Step 9: Installation Destination
Click Installation Destination

Confirm your 25GB disk is selected
Click Done

Step 10: Set Root Password
Click Root Password under "USER SETTINGS"

Set: redhat or (user wish)but make sure do not to forgot the root password
Enable Allow root SSH login with password
Click Done

Step 11: Begin Installation
Click Begin Installation

Wait until installation completes

🎯 Final Setup Steps
Reboot when prompted
Eject ISO from virtual drive

🥳 Congratulations! Your RHEL 9 virtual machine is ready for use.

💡 Recommendations & Best Practices
🌟 Pro Tips
💾 Take a snapshot right after installation
🔁 Enable bidirectional clipboard and drag-and-drop
🆕 Update system after first login:

bash
Copy
Edit
sudo dnf update -y

✅ Quick Summary
2GB RAM, 2 CPUs, 25GB disk
Install RHEL 9 via ISO
Tweak settings for smooth performance
Ready for Day 2 of Linux exploration!

💬 Let’s Connect! https://www.linkedin.com/in/dinesharumugam86/
Feel free to share your thoughts or questions, or even join me on this challenge. Let’s grow those real-world Linux skills together.