Cybersecurity reference sheets
The command line, networking, and security fundamentals every analyst uses.
Intro to the Terminal
The essential Linux command line for cybersecurity: moving around the file system, reading files, and chaining commands with pipes to pull answers out of a data file.
Text Processing & Pipelines
Chain grep, cut, sort, uniq, wc, and a little awk/sed with pipes to pull answers — like top attacking IPs or failed-login counts — straight out of raw log files and CSVs.
Regular Expressions (Regex)
A practical regex reference for reading logs: core tokens, character classes, quantifiers, anchors, groups, and ready-to-use IP and email patterns for grep -E.
Linux File Permissions
How Linux controls who can read, write, and execute every file — the rwx model, reading ls -l, and setting permissions with chmod, chown, and chgrp.
Managing User Accounts
Creating, editing, and removing user accounts as a security control on Linux and Windows — least privilege, seeing who has access, and the useradd/usermod/userdel and net user/PowerShell command sets.
Number Systems: Binary, Decimal & Hex
How binary, decimal, and hexadecimal represent numbers, how to convert between them, and why bits, bytes, and hex underpin IP addresses, colors, and hex dumps in cybersecurity.
Networking Commands
The core command-line tools for diagnosing and mapping a network — testing reachability, reading your own address, listing open ports, resolving names, tracing paths, and inspecting the local ARP table.
Common Ports & Protocols
A quick-reference map of the well-known TCP/UDP ports and the protocols behind them, which ones are insecure, and the encrypted services that replace them.
The CIA Triad & Security Principles
The three goals every security control protects (Confidentiality, Integrity, and Availability), plus the AAA model and the core design principles like least privilege, defense in depth, and failing securely that keep them intact.
Common Cyber Attacks
How the most common cyber attacks work, the warning sign that reveals each one, and the primary defense that stops it.
Malware Types
A defender's guide to the nine core malware families — virus, worm, trojan, ransomware, spyware, adware, rootkit, keylogger, and botnet — covering what each one is, how it spreads, and how to stop it.
Cryptography & Hashing Basics
How encryption keeps data secret and hashing proves it was not changed, covering symmetric versus asymmetric ciphers, SHA-256 versus the broken MD5 and SHA-1, salting passwords, and where HTTPS and TLS tie them together.