Daily Linux and cybersecurity lessons — paired with a real, interactive terminal you can practice in. Type commands, explore a virtual filesystem, and learn by doing.
Every Linux journey starts with three commands: `pwd` (where am I?), `ls` (what's here?) and `cd` (go somewhere).
Try `pwd` to print your current directory, then `ls -la` to list everything including hidden files. Use `cd notes` to enter a folder and `cd ..` to go back up.
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2026-06-16🐧 Linux
Reading files without opening an editor
`cat` prints a whole file. For big files use `head` (first lines) and `tail` (last lines). Search inside files with `grep`.
Try `cat welcome.txt`, then `grep linux notes/linux-basics.md` to find a word.
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2026-06-14🛡️ Security
What is the CIA triad?
Security rests on three pillars — Confidentiality, Integrity, Availability. Every control you'll ever deploy protects at least one of them.
As a SOC analyst, most alerts map to a threat against one pillar: data theft (C), tampering (I), or denial of service (A).
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2026-06-12🛰️ Networking
Ports, protocols & the TCP handshake
Services listen on ports: HTTP on 80, HTTPS on 443, SSH on 22. A TCP connection opens with a three-way handshake: SYN → SYN/ACK → ACK.
Knowing default ports lets you read a packet capture or a scan result at a glance.
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02CTF Challenges
Capture the flag — prove it in the terminal
0/ 80 pts
0/4 solved🏅 Visitor
Who am I?
10 pts
Every investigation starts by knowing your identity on the box. Run the command in the lab terminal and submit the username you are logged in as.
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Hidden in plain sight
25 pts
Some files hide behind a leading dot. List ALL files (including hidden ones) in your home directory, then read the secret file. Submit the flag inside it.
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Catch the brute-force
30 pts
A SOC analyst lives in the logs. Read /var/log/auth.log and find the IP address that repeatedly FAILED to log in as root. Submit that IP.
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Know your ports
15 pts
Networking 101 — read your networking notes and submit the port number used by HTTPS.
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03Terminal
Practice in a live shell
kamoliddin@kali-lab — webterm
Safe, simulated shell — nothing leaves your browser. ↑/↓ history, Tab to autocomplete.