Cheatsheets

Developer cheatsheets

Quick, searchable references for everyday commands and syntax — with in-depth recipes, examples, and troubleshooting on the deeper sheets.

43 cheatsheets

DevOps & tools

Git

Common git commands for branching, remotes, undoing, and inspecting history.

Docker

Everyday Docker & Compose commands for containers, images, and cleanup.

kubectl

Common Kubernetes commands for pods, deployments, networking, and contexts.

Bash / shell

Shell commands & operators for files, search, pipes, and processes.

Vim

Vim motions, editing, search/replace, and file commands.

Linux admin

systemd, users & permissions, packages, processes, and networking commands.

Semver

Semantic-versioning format and npm range operators.

GitHub Actions

Workflows, triggers, matrix builds, caching, secrets, permissions, and OIDC.

Terraform

init/plan/apply, state & backends, modules, variables, for_each, and drift.

Languages & syntax

SQL

SQL queries, joins, aggregation, DDL, and window functions.

PostgreSQL

EXPLAIN, index types, transactions & isolation, JSONB, VACUUM, and query tuning.

Python

Syntax, comprehensions, the standard library, idioms, OOP, and type hints.

TypeScript

Types, interfaces, generics, utility types, and narrowing.

JavaScript

Modern JavaScript: ES2020+ syntax, async/await, array methods, closures, and the gotchas.

Go

Packages, structs & interfaces, goroutines & channels, error handling, and modules.

Rust

Ownership, borrowing & lifetimes, enums & pattern matching, Result/Option, and traits.

Java

Classes, generics, collections, streams & lambdas, records, and exceptions.

C++

Modern C++: RAII, smart pointers, move semantics, the STL, templates, and UB pitfalls.

C#

Modern C#: records, LINQ, async/await, pattern matching, and nullable reference types.

PHP

Modern PHP 8: types, arrays, classes & traits, enums, the match expression, Composer, and PDO.

Ruby

Objects everywhere: blocks, hashes, modules & mixins, iterators, and idioms.

Kotlin

Null safety, data classes, lambdas, collections, scope functions, and coroutines.

Swift

Optionals, structs vs classes, enums with associated values, protocols, and closures.

Regular expressions

Regex tokens — character classes, anchors, quantifiers, groups, and lookarounds.

Markdown

Markdown syntax for text, headings, lists, links, code, and tables.

Web

HTTP headers

HTTP request & response headers for caching, security, and CORS.

OpenAPI & REST

Resource design, methods, status codes, pagination, error shapes, versioning, and the OpenAPI document.

OAuth 2.0 & OIDC

Auth-code + PKCE, tokens, scopes, OIDC, and the common attacks with their mitigations.

Networking & security

Networking

Subnetting, ports, protocols & layers, and essential CLI tools — with a topology diagram.

Network security

OWASP Top 10, TLS, auth & access, hardening, and security tooling.

Nginx

Location matching, reverse proxy, TLS, proxy headers, caching, and rate limiting.

Embedded & hardware

VHDL

Entities, architectures, types, concurrent & sequential (process) statements.

Verilog

Modules, wire/reg, blocking vs non-blocking, and always blocks.

8051 (MCS-51)

Registers, SFRs & ports, addressing modes, and common assembly instructions.

C

Types, pointers & memory, control flow, the preprocessor, and bit operations.

CS fundamentals

Data structures & Big-O

Complexity classes plus the core structures, traversals, and sorts.

Testing strategy

Test levels, the pyramid vs the trophy, doubles, flaky-test fixes, and Vitest & Playwright.

Architecture & systems

Microservices

Patterns, communication, data, and resilience for microservice architectures — with a reference diagram.

System design

Scaling, caching, databases, load balancing, messaging, and estimation — with a reference diagram.

Redis

Data types, TTL & eviction, caching patterns, locks, streams, and persistence.

IoT

Internet of Things — architecture layers, protocols, connectivity, and security, with a reference diagram.

IIoT

Industrial IoT — the Purdue model, industrial protocols, edge analytics, and OT security.

Full-stack + AI skills

A modern reference across frontend, backend, data, DevOps, and AI/LLM engineering.