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Seif Eldien Ahmad Mohammad
Seif Eldien Ahmad Mohammad

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🚀 My Journey with Red Hat System Administration (RHSA) — What I Learned and What’s Next

Over the last few weeks, I took a deep dive into the world of Linux system administration by studying the Red Hat System Administration (RHSA) course — not for the certification, but for the knowledge. As a student in cybersecurity aiming to specialize in Red Teaming, understanding Linux inside-out is a must.

Although I didn’t pursue the official certificate this time, I focused on understanding and practicing the core concepts. Here’s a breakdown of what I learned and what I’m working on right now.


🧠 What I Learned

  1. 🧬 The Evolution: From Unix to Linux to Modern Distros

Understanding the history of Unix and the philosophy behind Linux was an eye-opener. I learned how:

Unix influenced the modular and powerful nature of Linux

Different Linux distributions emerged for different purposes (e.g., Red Hat for enterprise, Debian for stability, Arch for customization, etc.)

System architecture is structured, and how it differs slightly across distros

  1. 📁 File Control

I learned how to:

Navigate the Linux filesystem efficiently using cd, ls, pwd, and tree

Work with files and directories: cp, mv, rm, touch, mkdir

Use redirection and piping (>, >>, <, |) to control input/output flows

  1. 👥 User Control

Managing users is critical in system security. I practiced:

Creating/deleting users with useradd, userdel

Modifying user data with usermod, passwd

Switching and working as different users with su and sudo

Managing user profiles and login behavior

  1. 🔐 Permissions & Groups

Security starts with permissions. I explored:

Understanding file permissions (rwx, numbers like chmod 755)

Changing ownership with chown, and permissions with chmod

Managing groups with groupadd, usermod -aG, etc.

The concept of umask and default permissions

  1. 🔍 Searching and Filtering

I got comfortable using:

find for locating files based on size, time, name

grep and its power in filtering and pattern matching

Combining tools like grep | sort | uniq for advanced filtering

  1. 💻 Shell Scripting (Bash)

This was the most fun part! I wrote scripts that:

Automate repetitive tasks

Handle user input, arguments, loops, and conditions

Include logging, backups, and simple error checking

  1. 🌟 Wildcards

I learned to use:

*, ?, [] in powerful ways to match patterns in filenames or command-line arguments

Combine wildcards with other tools like ls, rm, and grep to make powerful one-liners

  1. 🔎 Regular Expressions (Regex)

Regex felt like magic. I used it to:

Match complex patterns in logs and text files

Filter email addresses, IPs, error messages

Combine it with tools like grep, sed, awk

  1. ⏰ Task Scheduling with Cron

Task scheduling is a must-have for system admins. I learned how to:

Use crontab to schedule repetitive tasks like backups and script execution

Understand cron time syntax

Manage both user-level and system-wide jobs

Example:

0 3 * * * /home/user/backup.sh

This runs a backup script every day at 3 AM.


🛠️ What's Next — The Practical Phase

I'm now in the practical application phase — where I'm:

Building and managing a virtual Linux environment (using VirtualBox + CentOS & Ubuntu)

Writing daily-use scripts (e.g., backup automation, user report generation)

Practicing security hardening techniques

Exploring log management and cron job automation

The goal is to move from “I know how this works” to “I can build and maintain this myself”.


🎯 Final Thoughts

Although I didn't aim for the certification yet, this learning path has strengthened my confidence in handling Linux systems — which is essential for my Red Teaming journey. I plan to continue building my skills with:

CTFs focused on Linux exploitation

More advanced Bash scripting projects

Networking and system hardening practices

By the way, some people know me as Seif Eldin Ahmed Mohamed or Seif A. Mohammad - but I'm always Seif Eldien Ahmad Mohammad 😄. I had to assure my name is spelt right.

Thanks for reading. If you're also on a similar path or learning RHSA, feel free to connect — let’s grow together!


🔗 Let’s connect:

LinkedIn: https://www.linkedin.com/in/seifeldienahmad/

GitHub: https://github.com/SeifEldienAhmad/

Website: https://seifeldienahmad.github.io/

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