You have learned to navigate a Linux filesystem, read and change file permissions, install packages with apt, and build text-processing pipelines with grep, sort, and uniq. This lesson puts those skills directly to work in a security context and introduces the network-facing tools that come up in almost every penetration test.
Prerequisites: linux-basics-part1 and linux-basics-part2.
What is new here. The navigation and pipeline skills you already have are the foundation. This lesson adds the primary tool that bridges the shell and the network:
- **
curlandwget— make HTTP requests** from the terminal. HTTP is the protocol a browser uses to ask a server for a page; the server replies with a status code (like200for success or404for not found) and a body (the content itself).curldoes exactly the same thing from the command line, printing the response body to standard output so you can pipe it intogrepor save it to a file. The full picture of HTTP — methods, APIs, JSON — is covered inpython-primer; for now this one-liner mental model is enough.
You will practise the fetch-then-filter pattern — curl | grep — that threads this tool into the pipelines you already know. This is the one-liner shape that recurs throughout the course whenever you want to pull endpoints, links, or interesting strings out of a live web response.
The lesson also introduces three other network tools — nc, ssh, and dig — for awareness. You will not be tested on them here; they appear in detail in later lessons.
In this lesson you will:
- Apply shell navigation and
grepto inspect a real file (/etc/passwd) with security context. - Write a **
curl | grep** one-liner that fetches a page and extracts links from it. - Meet the full essential pentest CLI:
curl,wget,nc,ssh, anddig.
Target for the hands-on steps: any Linux shell — Kali, WSL, or the lab from testing-lab-docker-kali. No internet target is required for most steps.
Estimated time: eight to ten minutes.
When you are ready, send the Continue signal.