EXPLORE THE CURRICULUM
Level 0 · Computer foundations
Learn your way around terminals, operating systems and networks.
Before you begin Start here with no prerequisites · Step 1–40
40 lessons
Reset filtersL0PowerShell & WindowsStep 1–1515 lessons
- 001 First Steps in PowerShell — Driving Your Computer with TextOpen PowerShell and read your current location from the prompt
- 002 Working with Files — Create, Copy, Move, DeleteCreate files and folders with New-Item
- 003 The Pipe (|) — A Way of Thinking That Assembles CommandsPass a command's output into the next command's input with the pipe (|)
- 004 Text Processing — Finding a Needle in the LogsRead files with Get-Content, and peek at just the beginning of long files
- 005 Collecting System Information — A Health Checkup for My ComputerCollect OS and hardware info with Get-ComputerInfo and pick out only the items you need
- 006 Checking the Network — Inspecting My Computer's Outside LinesFind and explain your PC's IP address, default gateway, and DNS server
- 007 Variables and Data Types — Putting Values into Labeled BoxesStore values in variables and pull them back out
- 008 Conditionals and Loops — Making the Computer Judge and ToilTurn "if ~ then" judgments into code with if/else
- 009 Execution Policy and Your First Script — Meeting Windows' Safety Lock Head-OnSave a bundle of commands as a .ps1 script file and run it
- 010 ★ Project: Automatic File Classification — A Robot That Cleans Your Downloads FolderDesign the algorithm (processing order) in plain language before writing code
- 011 Exploring the Registry — Opening Windows' VaultExplain the registry as "a tree structure of keys and values"
- 012 Event Logs — Reading Windows' Black BoxOpen an administrator PowerShell and explain why this privilege is used "only when needed"
- 013 Inside Processes and Services — Trace the Lineage of ExecutionExplain what a PID is and why processes are identified by number rather than name
- 014 Remote Management — Commanding a Computer Across the NetworkExplain what a remote session is, and the role and port numbers of WinRM/PSRemoting
- 015 ★ Project: What Happens After Boot? — A Full Survey of Auto-Start LocationsExplain what persistence is and why attackers use "doors that already exist"
L0Linux & your labStep 16–3015 lessons
- 016 Understanding Virtualization — Building a Computer Inside a ComputerExplain what a virtual machine (VM) and a hypervisor are
- 017 Installing Ubuntu and Snapshots — Moving Into the Lab and Setting Save PointsExplain what an ISO file and LTS are
- 018 Linux Basic Commands 1 — Finding Your Way in the Black WindowExplain that the Linux filesystem is a single tree rooted at /
- 019 Linux Basic Commands 2 — Three Pipes for Steering OutputExplain the three standard streams (stdin/stdout/stderr) along with their numbers
- 020 Searching (grep/find) — Finding Two Needles in a HaystackExplain the difference in roles between grep (content search) and find (name/condition search)
- 021 Package Management — apt, Linux's App StoreExplain the three concepts of package, repository, and dependency
- 022 Editors — Surviving the Terminal with nano and vimExplain why terminal editors are needed, and why cat or > isn't enough
- 023 Permissions 1 — rwx, Rules Carved Into FilesInterpret a string like -rwxr-xr-- at the front of ls -l output, class by class
- 024 Permissions 2 — Ownership and sudo: How to Wield PowerExplain what root (UID 0) is and why it bypasses permission checks
- 025 User Management Lab — Crossing the Boundary Between Authentication and AuthorizationExplain the difference between authentication and authorization with examples
- 026 Process Management — List Them, Find Them, Signal ThemView the list of running processes and find each one's PID (number) and PPID (parent's number)
- 027 Exploring the Directory Structure — Putting the Linux Map in Your HandsExplain the roles of Linux's top-level folders (/etc, /var, /bin, etc.)
- 028 bash Scripts and cron — Hand Your Typed Commands Over to an Alarm ClockCreate a shell script that gathers several commands in a file and runs them at once
- 029 SSH Remote Access — Opening the Encrypted Front GateExplain what SSH is and which problem of plaintext communication it solves
- 030 ★ Project: Monitoring Automation — Building a Watcher That Works AloneExplain what monitoring is and why "records" become the baseline of normal
L0Network foundationsStep 31–4010 lessons
- 031 Understanding IP Addresses Completely — Neighborhood Name and House NumberExplain that an IPv4 address is actually a 32-bit number
- 032 MAC Addresses and ARP — The Real Address on the WireExplain the difference between IP and MAC addresses from three perspectives (who assigns it, does it change, w…
- 033 DNS — The Internet's Phone BookExplain that DNS is a hierarchical system that converts "name → IP"
- 034 Ports and Services — Room Numbers Inside the BuildingExplain what a port is and how it differs from an IP (building and room number)
- 035 TCP Deep Dive — The Art of the HandshakeExplain what it means that TCP is "connection-oriented"
- 036 UDP and ICMP — The Courier Who Throws and the Status HotlineExplain the difference between TCP and UDP by the criterion "is it meaningful to receive the missing piece aga…
- 037 Routing and Gateways — Follow the Letter's JourneyExplain what a router and a hop are
- 038 NAT and Home Routers — The Secret of the Disguise-Managing DoorstepRecite the three private IP ranges and tell whether a given address is private or public
- 039 The OSI 7 Layers — A Map for Placing Nine PiecesRecite the OSI 7 layers in order and describe each layer's role in one line
- 040 Level 0 Comprehensive Test — Examining YourselfPinpoint what you know and what you don't across all of Level 0