75 Linux Commands

75 Linux Commands

Linux Family Tree

Linux Family Tree

Networking Fundamentals – Routing | Switching | Firewall

Networking Fundamentals – Routing | Switching | Firewall

sudo vs su

sudo vs su

What Happens When You Connect to Wi-Fi?

What Happens When You Connect to Wi-Fi?

How VPN Works | IT Support Essentials

 How VPN Works | IT Support Essentials

command: sudo rm -rf /

One of the Most Dangerous Linux Commands You Should Never Run on your Linux machine.

command: sudo rm -rf /

If you are learning Linux or working in production environments, this command is extremely dangerous.

Let’s explain:

• sudo → Run as superuser (root access)
• rm → Remove files
• -r → Delete recursively (folders + contents)
• -f → Force delete (no confirmation)
• / → Root directory (entire system)

This command attempts to delete everything from the root directory. within 5 to 10 min the system will shutdown. So, You can do anything on linux.

Why am I sharing this?
Because many beginners copy commands from the internet without understanding them.

Before running any command:

• Understand what it does
• Test in lab environment
• Never run unknown commands in production

Linux gives you power.
But power without knowledge is dangerous.

Windows Server Hardening Checklist

 Windows Server Hardening Checklist

Linux Server Hardening Checklist

Linux Server Hardening Checklist – Secure Your Infrastructure Before Attackers Do!

Linux servers power most of today’s cloud, DevOps, and enterprise environments. But leaving them with default settings can expose your infrastructure to serious security risks.
Here is a 14-Point Linux Server Hardening Checklist every system administrator and security professional should follow:

✅ 1. Keep System Updated:  Regularly update OS packages and security patches.
✅ 2. Disable Root Login:  Prevent direct root SSH login to reduce attack surface.
✅ 3. Use Strong Password Policies:  Enforce complexity, expiration, and lockout rules.
✅ 4. Configure SSH Security:  Change default SSH port, disable password auth, and use key-based authentication.
✅ 5. Enable Firewall (UFW / iptables / firewalld):  Allow only necessary ports and services.
✅ 6. Install Intrusion Detection Systems (IDS):  Use tools like Fail2Ban, AIDE, or OSSEC.
✅ 7. Disable Unnecessary Services:  Remove or disable unused applications and daemons.
✅ 8. Implement Least Privilege Access:  Grant only required permissions to users and services.
✅ 9. Secure File Permissions:  Audit and restrict access to sensitive system files.
✅ 10. Enable Logging & Monitoring:  Use syslog, auditd, or centralized monitoring solutions.
✅ 11. Configure Automatic Security Updates:  Reduce risk of vulnerabilities with unattended upgrades.
✅ 12. Protect Against Brute Force Attacks:  Deploy Fail2Ban or similar tools.
✅ 13. Encrypt Data & Backup Regularly:  Use disk encryption and maintain secure backups.
✅ 14. Perform Regular Security Audits & Scans:  Use tools like Lynis, OpenSCAP, or Nessus.

System Engineer vs Network Engineer

System Engineer vs Network Engineer