$ ls ./tools

tools

OSI Model — Deep Explorer

Interactive 7-layer reference: animated encapsulation, bit-level header decoders, a 93-protocol atlas, port reference, per-layer attack surface, and flashcards.

NetworkingOSIReference

Number Bases — Conversion Trainer

Binary, hex, and decimal made visual: a live bit builder, step-by-step conversion walkthroughs, bitwise operations explained from zero, and scored practice.

FundamentalsBinaryPractice

Subnetting — Mask & Range Trainer

Subnet masks made visual: a live network/host line builder, block-size walkthroughs that solve subnet/broadcast/range, scored practice, and the /24–/30 matrix.

NetworkingSubnettingPractice

Text Drills — Commands to Pipes

Fill-in-the-blank drills for head, tail, wc, cut, sort, uniq, grep, tr, and awk: drill one command at a time or work up to multi-stage pipes. Every answer is graded against real GNU output.

LinuxText ProcessingPractice