Programming Languages Cheat Sheets
Syntax, built-in functions and everyday patterns for the most used languages and formats. For SQL, see the SQL sheet under Databases & Data.
Bash Scripting
Writing Bash scripts: safe script setup, variables, parameter expansion, tests, loops, arrays, functions, redirection and error handling. Targets Bash 5.2 (most of it works from Bash 4; macOS still ships 3.2, so install a newer Bash there).
C
Quick reference for C: compiling with gcc/clang, types, printf formats, pointers, strings, memory and the preprocessor. Targets C17, with C23 additions marked "(C23)".
C#
Microsoft's typed, object-oriented language for apps, games (Unity), web APIs and tools on .NET. This sheet targets C# 14 with .NET 10 and marks features that need a recent version.
C++
Quick reference for modern C++: compiling, strings, STL containers and algorithms, lambdas, classes, smart pointers, templates and concepts. Targets C++20, with C++23 features marked "(C++23)".
CSS
The language that styles web pages: selectors, the cascade, box model, flexbox, grid, responsive design and modern features. Browser support notes use web.dev Baseline status as of October 2026.
HTML
The markup language that gives every web page its structure: elements, attributes, forms, media and accessibility basics. Targets the current HTML Living Standard and browsers as of October 2026.
JavaScript & TypeScript
Modern JavaScript (up to ES2025) for browsers and Node.js, then TypeScript (5.x to 7.0) on top: types, generics, narrowing and project setup. Tags like (ES2022) show when a feature arrived; everything here runs in current browsers and Node 22+.
JSON
JSON is the standard text format for data in APIs and config files (RFC 8259). Syntax rules, common mistakes, JSON in JavaScript and Python, jq on the command line (jq 1.7+) and JSON Schema basics.
PHP
Server-side language for websites, forms, APIs and databases. This sheet targets PHP 8.4 and marks features that need PHP 8.0 or later.
Python
Everyday Python syntax, built-ins and standard library on one page. Targets Python 3.12 and newer; features that need a specific version are marked, e.g. (3.10+).
Regex
Patterns for finding, checking and replacing text: syntax, flags, ready-made patterns (email, URL, dates, Belgian phone/IBAN…) and how regex works in JavaScript, Python, PHP, C#, grep, sed and VS Code. Test your patterns at regex101.com.