Developer Cheatsheet

One-page Git command reference covering commit & stash, branch create/merge/rebase, revert & recovery, remote collaboration, and git log history queries — 50+ common operations for daily collaboration and recovering from mistakes.

A Vim operation reference covering cursor motion, text editing, search and replace, visual mode, and save/exit, aimed at developers and operators editing files on a server, including real-world tricks such as batch replacement and saving with sudo.

A Systemd service-management reference covering start/stop and boot-enabling, journalctl log viewing, timer scheduling, targets and runlevels, and resource limits, with the differences between easily-confused pairs such as reload vs restart and mask vs disable.

A Cron scheduling reference spanning the 5-field expression format, special characters and time macros, common examples, environment variables, and troubleshooting, flagging frequent pitfalls such as the OR relationship between day-of-month and day-of-week and the minimal default PATH.

A debugging reference for GitHub Actions, GitLab CI, and Jenkins pipelines, covering job reruns and log extraction, runner online status, cache and disk usage, and local reproduction with act or gitlab-runner exec.

An MQ operations reference for Kafka, RabbitMQ, RocketMQ, and Redis Pub/Sub, focused on the four high-frequency scenarios of locating consumer backlog, hunting connection leaks, diagnosing cluster state, and benchmarking throughput.

An ES6+ syntax reference for frontend and full-stack developers: let/const, arrow functions, destructuring, template literals, higher-order array methods, and Promise/async-await — the patterns used most in everyday React/Vue and Node code, ready to reuse.

For Go developers building backend services, cloud-native tooling, and CLIs: covers variables & types, control flow, functions and defer, structs & methods, interfaces, goroutine/channel concurrency, and error handling, organized by the coding scenarios you hit in practice.

For Python developers doing data analysis, numerical computing, and scientific simulation: covers array creation, indexing & slicing, shape manipulation, math & statistics, random numbers, and the often-misunderstood broadcasting rule, arranged from creating an array to saving it to disk.

For Java backend and ops developers: covers compiling, running and packaging with javac/java/jar, Maven/Gradle build flows, JVM heap and GC tuning flags, and online troubleshooting with jps/jstack/jmap/jstat, organized in a build → run → tune → debug sequence you can copy.

For PHP developers and the ops people deploying PHP apps: covers running scripts and the built-in dev server, Composer dependency management, extension and ini config checks, php -l linting and phpinfo diagnostics, grouped by the real dev workflow.

An Nginx configuration handbook for backend, DevOps, and frontend-integration engineers, covering nginx -t/-s reload syntax validation and hot reload, location matching priority, proxy_pass reverse proxies, access/error log troubleshooting, and the common causes of 502/504.

A curl request and troubleshooting handbook for backend developers, testers, and ops, covering GET/POST request bodies, -v/-I/-w request details and timing analysis, -k/-x TLS and proxies, -u/-F/-o auth and upload, plus practical combinations of cookies, redirects, and timeout retries.

An HTML reference for building accessible, semantic web pages — document structure, text, lists, links & images, tables, forms, and the semantic tags that convey meaning to both browsers and screen readers.

A CSS reference for styling pages without a framework, covering selectors, the box model, Flex/Grid layout, positioning, transitions & animation, and responsive patterns for both desktop and mobile.

An Emmet abbreviation reference for anyone writing HTML/CSS by hand in VSCode, covering structure expansion, nesting & grouping, attribute and counter shortcuts, and CSS shorthand that turns long markup into a single keystroke.

A MySQL command handbook for DBAs, backends, and data analysts, covering database & table management, CRUD, index optimization and slow-query localization with EXPLAIN, user privileges, logical backup & recovery, and replication — highlighting operations that can lock tables or stall replication.

A PostgreSQL command handbook for backend engineers, DBAs, and data analysts, covering connection & role management, database & table operations, EXPLAIN analysis, lock & transaction troubleshooting, pg_dump/pg_restore backup & recovery, and streaming replication, with paths for locating lock waits and table bloat.

A Redis command handbook for the cache/backend and its operators, covering string and per-data-structure operations, key space and TTL management, RDB/AOF persistence trade-offs, memory and big-key inspection, slow query monitoring, cluster & replication, and practical debugging of hot keys, big keys, and cache puncturing/cascading.

A MongoDB reference for backend engineers, covering database & collection management, document CRUD, query operators, index strategies that keep queries off full collection scans, the aggregation pipeline, and replica-set vs sharded-cluster responsibilities.

A Neo4j Cypher reference for working with graph data where relationships matter more than rows, covering node & relationship creation, pattern matching, updates & deletes, aggregation and ordering, constraints & indexes, and traversal-style graph queries.

A kubectl command handbook for app developers and cluster operators, covering Pod query & log diagnosis, deployment scaling & rolling updates, context & namespace switching, and event troubleshooting, with full debugging paths for CrashLoopBackOff and ImagePullBackOff.

A Docker Compose command handbook for frontend, backend, and DevOps engineers who manage several services as one unit, covering multi-service orchestration, log tracking & status inspection, config validation & build, network & named volume management, and horizontal scaling, with mitigation and troubleshooting for frequent incidents like down -v data loss and --scale port conflicts.

A Dockerfile writing reference for developers who package applications into images, covering base image selection, RUN execution, COPY/ADD file handling, ENV variables, port declaration, multi-stage builds, and layer size optimization — with the build cache and .dockerignore pitfalls that silently blow up image size.

HTTP methods and REST semantics: GET/POST/PUT/PATCH/DELETE verbs, idempotency, safe methods, status-code pairing and common misuses. For choosing the right verb when designing APIs so retries and concurrency behave predictably. Pairs with the HTTP Status Codes sheet.

Every HTTP response status code from 1xx to 5xx with its meaning, common cause and a debugging hint. Built for backend/frontend developers and Nginx/gateway ops to pinpoint why an API misbehaves — distinguishing 4xx from 5xx and checking whether redirects behave as expected.

A Markdown syntax reference covering headings, text formatting, links & images, lists, code blocks, tables, blockquotes and GFM extensions, with cross-platform caveats. For writing technical docs, READMEs and blog posts that stay clean and portable.

LaTeX commands for academic typesetting, grouped into document structure, text formatting, math formulas, list environments, tables/figures and references. For writing papers, reports and theses in LaTeX rather than fighting the tool.

ASCII codes for control and printable characters, each shown in decimal, hex, octal and HTML-entity forms, plus notes on Latin-1 extension and how to convert codes in common programming languages. For encoding and protocol debugging.

Emacs keystrokes covering file & buffer operations, cursor movement and editing, search/replace, window management, keyboard macros and Org-mode, with the C/M prefix conventions explained. For terminal or no-GUI editing where Vim-style modal editing is not an option.

Prompt-design patterns and templates for ChatGPT: role assignment, task framing and step breakdown, output-format constraints, few-shot examples and chain-of-thought steering — with common office, coding and writing scenarios. For turning vague asks into consistent, controllable model output.

Pandoc conversion commands across Markdown/HTML/PDF/DOCX/EPUB interchange, Chinese PDF typesetting and fonts, custom templates and styles, slides and e-books, citations and math. For converting documents without re-keying content or breaking layout.

Homebrew commands for installing/updating/removing formulas, managing Cask GUI apps, starting and stopping services, switching to domestic mirrors, and inspecting dependencies and debugging broken installs. For keeping a macOS dev environment reproducible.

XPath selector syntax: node paths, predicate filtering, axis navigation, string/functions and wildcard/logic, plus XML/HTML parsing and scraping patterns. For locating elements precisely in XML, HTML or config files without brittle regex.

For developers shipping with Docker and slimming images: explains .dockerignore glob matching, ignoring files and directories, differences from .gitignore, build-context slimming tips and common pitfalls. A correct ignore file sharply shrinks the context sent to the daemon.

A YAML syntax reference for developers who write Docker Compose, Kubernetes and GitHub Actions configs, covering basic syntax, data types, lists, dicts, multiline strings, anchors and explicit type tags. Consult section by section while validating indentation and common write errors.

A JSON reference for frontend/backend developers who handle API payloads and JSON config, covering data types, objects, arrays, nesting, common API response patterns, and validation/formatting commands. Consult section by section when a key quotation, comma or nested brace causes an error.

A TOML reference for developers writing Rust/Cargo, Hugo and Python pyproject.toml config, covering basic types, date-time, strings, arrays and tables, arrays of tables, and a Cargo.toml example. Section-by-section lookup helps avoid type and structure ambiguity.

An INI reference for developers working with Windows config, PHP php.ini, Git config and Python configparser files, covering basic syntax, data types, common real-world sections and cross-parser pitfalls.

Command reference for Kilo Code CLI, the terminal AI coding agent sharing an engine with the IDE extensions: install, interactive & one-off tasks, and model integrations, covering kilo run, kilo --mode, kilo --auto, kilo auth, and kilo mcp.

Command reference for Pi, the earendil-works multi-model terminal coding agent: install, interactive sessions, headless mode & scripting, and session/model management, covering pi -c, pi -p, pi @file, /login, and /model.

Command reference for Kimi Code CLI, Moonshot AI terminal AI coding agent wired to Kimi models: install, interactive & single instructions, and sessions & models, covering kimi -p, kimi -C, /login, /init, and /model.

Command reference for Grok CLI, the xAI Grok Build terminal AI coding agent: install, interactive sessions, session management, headless mode, and scripting, covering grok -p, grok inspect, XAI_API_KEY, and /model.

Command reference for Warp Agent CLI, the AI coding agent built into the Warp terminal: install, core agent commands, MCP integration, and cloud agents, covering /agent, /model, /plan, /orchestrate, /mcp, and oz agent run.

Retrieval-Augmented Generation (RAG) prompt patterns covering answer-only-from-context, cite sources, handle no-answer, fuse multi-passage evidence, and flag conflicts — emphasizing traceability and hallucination control.

Autonomous-agent system-prompt patterns covering goal/role definition, tool declarations, step-by-step decision loops, guardrails & permissions, error handling, and reflection — emphasizing control and safety.

Model-agnostic text-to-image (Midjourney/Stable Diffusion/SDXL) prompt structure covering subject, style & artists, composition & lens, light & material, negative prompts, and common params.

Code-generation prompt patterns covering requirement & context handoff, language/framework/version constraints, I/O contracts, edge cases & tests, and acceptance criteria — emphasizing compilable, runnable output.

Prompt-writing reference for DeepSeek that distinguishes the reasoning model R1 (deepseek-reasoner) from the chat model V3 (deepseek-chat), covering R1 hard rules (no system prompt, instructions in user, no few-shot, temperature 0.6) and V3 system-lock, few-shot, and JSON/function calling.

A keyboard-shortcut reference for Windows desktop and multi-monitor users, covering General, File Explorer, Screenshots, Window Management, System, and Command Line — 30+ high-frequency bindings from snapping windows to opening Task Manager in one step.

A Chrome keyboard-shortcut reference for daily browsing and front-end debugging, covering Tabs, Windows, Browsing, Address Bar, DevTools and Mouse — 6 groups with 25+ high-frequency bindings on both macOS and Windows.

A Slack keyboard-shortcut reference for team members who rely on Slack across many channels and threads, covering Messages, Channels, Navigation, Search and Formatting — 20+ high-frequency bindings on macOS and Windows.