Reference index

19 entries

01
Commands
awk - Extract Columns and Transform Text
Learn awk in 5 minutes. Extract columns from files, parse CSVs, and process text data without writing a script.
02
Concepts
Capture the Flag (CTF)
What CTF competitions are, how they work, and why they matter for learning security skills
03
Commands
cat - Read Files in the Terminal
Learn cat for displaying file contents. The simplest way to read files and start pipelines.
04
Game guides
Chess at CLI-Games
Puzzles, vision training, blindfold mode, and AI opponents - all from the command line
05
Game guides
Chess Opening Principles - Stop Losing in the First 10 Moves
Learn the 4 opening principles that separate beginners from intermediate players. No memorization required.
06
Commands
cut - Extract Columns the Simple Way
Learn cut for extracting columns from text. Simpler than awk for basic field extraction.
07
Game guides
Dial-Up Days: Getting Started
Essential information for new players
08
Commands
find - Locate Files by Name, Type, or Age
Learn find to locate files anywhere on your system. Search by name, size, date, or type without memorizing your folder structure.
09
Commands
grep - Search for Text in Files
Learn grep to search files for patterns. Find errors in logs, locate config values, and filter output instantly.
10
Commands
head - See the First Lines
Learn head for viewing the beginning of files. Quick previews and extracting top results.
11
Commands
sed - Find and Replace from the Command Line
Learn sed for find-and-replace in files. Fix typos, transform text, and edit without opening an editor.
12
Commands
sort - Put Lines in Order
Learn sort for ordering text. Alphabetical, numerical, by column - essential for data analysis pipelines.
13
Commands
tail - See the Last Lines
Learn tail for viewing the end of files. Check recent logs and grab bottom results.
14
Game guides
The Accidental Series
A medieval comedy crawlers where a turnip farmer stumbles into legend
15
Game guides
The Network
Every player is a host on a shared network — identity, discovery, firewalls, and the infrastructure that ties it all together
16
Commands
tr - Translate and Transform Characters
Learn tr for character translation. Convert case, delete characters, decode ROT13 - all in one command.
17
Commands
uniq - Count and Remove Duplicates
Learn uniq for counting duplicates and finding repeated patterns. Essential for frequency analysis.
18
Commands
wc - Count Lines, Words, and Characters
Learn wc for counting lines, words, and bytes. Quick stats on files and pipeline output.
19
Game guides
Wordie
Daily word puzzle with streaks, hard mode, and no ads between you and the game

Reference index

awk - Extract Columns and Transform Text

Capture the Flag (CTF)

cat - Read Files in the Terminal

Chess at CLI-Games

Chess Opening Principles - Stop Losing in the First 10 Moves

cut - Extract Columns the Simple Way

Dial-Up Days: Getting Started

find - Locate Files by Name, Type, or Age

grep - Search for Text in Files

head - See the First Lines

sed - Find and Replace from the Command Line

sort - Put Lines in Order

tail - See the Last Lines

The Accidental Series

The Network

tr - Translate and Transform Characters

uniq - Count and Remove Duplicates

wc - Count Lines, Words, and Characters

Wordie