Nexus Cheatsheets

Analytics libraries: quick reference and cheatsheet.

Google Analytics's analytics.js is deprecated.

Mixpanel: quick reference and cheatsheet.

Ansible: playbooks, modules, and configuration patterns.

Ansible examples: playbooks, modules, and configuration patterns.

Place your modules inside tasks.

Ansible is available as a package in most OS's.

Ansible roles: playbooks, modules, and configuration patterns.

Symbols view enables Ctags support for Atom.

Prefix with / to do a web search.

Inkscape: keyboard shortcuts and feature reference.

[Org mode](https://orgmode.org/) is for keeping hierarchal notes (and more) in Emacs.

Sketch: keyboard shortcuts and feature reference.

[Spacemacs](http://spacemacs.org) is a distribution for Emacs.

Replace ⌘ with Ctrl on Windows and Linux.

Weechat: keyboard shortcuts and feature reference.

This example should be fine for most projects indented by 2 spaces. See: animate.css editorconfig

[Visual Studio Code](https://code.visualstudio.com/), or VSCode, is an open-source code editor. This guide targets VSCode v1.19.

Quick reference for the [C macro preprocessor](https://en.m.wikipedia.org/wiki/C_preprocessor), which can be used independent of C/C++.

out is used to declare a variable at the point where it is passed as an argument.

Go (Golang): syntax, types, and standard library reference.

You'll need mplayer, imagemagick and gifsicle. This converts frames to .png, then turns them into an animated gif.

Quick reference to ANSI color codes.

This is a quick reference to getting started with Bash scripting.

Command Line Interface Pages: command-line usage, options, and examples.

Curl: command-line usage, options, and examples.

Emacs: command-line usage, options, and examples.

These conditions only work in MacOS and BSD-like systems (no GNU/Linux support).

In BRE, these characters have a special meaning unless they are escaped with a backslash:

[GnuPG](https://gnupg.org/) is a complete and free implementation of the OpenPGP standard.

= expressions are only evaluated when they're being used.

Man: command-line usage, options, and examples.

Pass: command-line usage, options, and examples.

Quick reference for SSH - secure remote access, key management, port forwarding, and configuration for encrypted connections.

Screen or GNU Screen is a terminal multiplexer. In other words, it means that you can start a screen session and then open any number of windows (virtual terminals). This does not contain **all** of screen's commands and options, read [GNU's manual](https://www.gnu.org/software/screen/manual/screen.html#Commands) to see everything

This creates a virtual file with the contents of the output of ls ./old.

YUM: command-line usage, options, and examples.

ffmpeg: command-line usage, options, and examples.

Quick reference for fzf - a blazing fast command-line fuzzy finder for interactive filtering of any list including files, command history, and processes.

ncftp: command-line usage, options, and examples.

pm2: command-line usage, options, and examples.

[rTorrent](https://rakshasa.github.io/rtorrent/) is a command-line torrent application. Here are some shortcut keys.

rclone: command-line usage, options, and examples.

rename: Perl-based file renaming utility with regex support.

scp: command-line usage, options, and examples.

Here's some hints on using sed.

POSIX sh scripting reference. Portable shell commands that work across all UNIX systems without bash/zsh dependencies. Essential for cross-platform scripts and containers.

Concatenate, Deflate, Inflate files

tmux: command-line usage, options, and examples.

See the processes in your Unix machine.

Quick reference for yazi - a blazing fast terminal file manager written in Rust with async I/O and a modern TUI interface.

Zsh is mostly compatible with Bash, so most everything in Bash's cheatsheet also applies.

Print the string with a trailing \n.

Rsync: command-line usage, options, and examples.

[mattgreen/watchexec](https://github.com/mattgreen/watchexec) runs commands whenever certain files change.

wait-for-device can be specified after adb to ensure that the command will run once the device is connected.

All composer commands, depending on your install, may need to use php composer.phar in the install folder for composer, instead of global/plain composer.

Cron: command-line usage, options, and examples.

Cask commands are used for interacting with graphical applications.

HTTPie is a command-line HTTP client.

AWK is a powerful text processing language for pattern scanning and processing. Named after its creators Aho, Weinberger, and Kernighan.

GNU Readline is a library that provides command-line editing and history capabilities for interactive programs like Bash, GDB, and Python REPL.

Bootstrap 4: flexbox grid, utility classes, cards, responsive navbar, and component reference.

CSS Grid: css properties, selectors, and styling reference.

Here's a 4-line snippet on how to get beautiful, antialiased text with CSS.

CSS tricks: css properties, selectors, and styling reference.

Tachyons is a functional CSS toolkit with composable utility classes for rapid UI development. Mobile-first, highly performant, and human-readable.

UIkit is a lightweight and modular CSS framework for developing fast and powerful web interfaces. Uses `uk-` prefix for all classes and attributes.

Bootstrap: css properties, selectors, and styling reference.

Wrap as many .column's' as you like in a .columns wrapper

CSS: css properties, selectors, and styling reference.

A fixed-height top bar and a dynamic-height content area.

This uses whatever system font is available. See: System shock - Designing Medium (medium.com)

Stylus: css properties, selectors, and styling reference.

cssnext: css properties, selectors, and styling reference.

This is a quick reference to Sass stylesheets.

[Knex](http://knexjs.org/) is an SQL query builder for Node.js. This guide targets v0.13.0.

MySQL: query syntax, schema design, and operations.

$ psql #logs in to default database & default user

> returns JSON, >> returns text.

Quick reference for SQL JOIN types, syntax, and patterns.

See: <https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/command-options.html>

Chef: configuration, deployment, and operations reference.

CircleCI: CI/CD configuration, jobs, workflows, and pipeline reference.

Deis: configuration, deployment, and operations reference.

Docker CLI: configuration, deployment, and operations reference.

Using shell will turn on strict mode for shell commands.

Flynn: configuration, deployment, and operations reference.

[Heroku](https://heroku.com/) is a web hosting platform supporting many languages, and this guide is a reference to Heroku's [command-line interface](https://heroku.com/).

Quick reference for [Travis CI](https://travis-ci.org) yaml configuration. See [official documentation](https://docs.travis-ci.com/user/customizing-the-build/).

[Vagrant](http://vagrantup.com) lets you build isolated virtual environments for your apps.

Vagrantfile: configuration, deployment, and operations reference.

Docker compose is now integrated into the official Docker installation. The functionality only improved over that change, and the simple syntax change is : V1 : docker-compose ARG to V2 docker compose

Most of these magic is defined in Kernel.SpecialForms.

ExUnit: elixir syntax, functions, and otp patterns.

Phoenix: Ecto: elixir syntax, functions, and otp patterns.

This is for Phoenix 1.2 and below. Phoenix 1.3 has a new API..

Erlang ETS: elixir syntax, functions, and otp patterns.

Install Erlang, Elixir, Node.js, PostgreSQL first.

See Phoenix for a more updated cheatsheet.

Creates a migration (no models).

See: Mix.Tasks.Phoenix.Routes (hexdocs.pm)

Phoenix: Plug.Conn: elixir syntax, functions, and otp patterns.

Elixir: elixir syntax, functions, and otp patterns.

Quick reference for Phoenix 1.3 with Ecto 2.x - legacy database integration for older Phoenix applications. Use Phoenix 1.7+ for new projects.

Creates a new branch locally then pushes it.

Quick reference to some utilities in the [git-extras](https://github.com/tj/git-extras) utilities.

A list of revision specifications you can use with `git log` and many other Git commands. Summarized from `gitrevisions(7)` man page.

Git tricks: git commands, workflows, and best practices.

git log: git commands, workflows, and best practices.

See the next tables on format variables.

You can substitute git log → tig.

Note that Appcache is deprecated!

<meta property="al:ios:url" content="applinks://docs" />

<link rel="shortcut icon" type="image/x-icon" href="/favicon.ico">

Inline your CSS as much as possible.

first-child: doesn't work for elements inserted via JS.

A bunch of bugs to take care of if you're going to target legacy IE browsers.

Microformats: html elements, attributes, and semantic markup.

Quick reference for SVG elements, attributes, paths, gradients, filters, and animations

Share links: html elements, attributes, and semantic markup.

These are CSS properties that will cause "layout thrashing". Avoid changing them to prevent bottlenecks in your UI performance.

See: OpenGraph protocol (developers.facebook.com)

datetime and datetime-local fields are not widely supported.

Test queries in the Xpath test bed:

Quick reference for MJML (Mailjet Markup Language) - responsive email markup language that makes coding responsive emails easy.

[Kotlin](http://kotlinlang.org/) is a statically typed programming language for modern multiplatform applications.

Asynchronous JavaScript And XML for making HTTP requests in the browser

Aurelia: conventions-based framework with dependency injection, two-way binding, and web component support.

Axios: promise-based HTTP client for browser and Node.js with interceptors and automatic JSON.

CanJS: MVVM framework with observables, stache templates, custom elements, and real-time data connections.

Saves: strokeStyle fillStyle globalAlpha lineWidth lineCap lineJoin miterLimit shadowOffsetX shadowOffsetY shadowBlur shadowColor

Chart.js: simple yet flexible charting library for line, bar, pie, radar, and more.

Quick reference to the HTML [DOM createRange API](https://devdocs.io/dom/range).

Quick introduction to the HTML [DOM selection API](https://devdocs.io/dom/selection).

JavaScript Arrays: javascript reference and quick guide.

.includes is ES6-only, otherwise use .indexOf(val) !== -1 if you don't polyfill.

A quick reference guide to building Progressive Web Apps (PWA) including manifest configuration, service worker lifecycle, caching strategies, and installability.

intro: A quick reference to the JavaScript Promise API.

SVG.js is a lightweight JavaScript library for manipulating and animating SVG elements. Quick reference for shapes, transforms, animations, and DOM operations.

Service Workers are scripts that run in the background, enabling offline capabilities, push notifications, and background sync for web applications.

Quick reference for Socket.io - a library for real-time, bidirectional, event-based communication between browsers and servers using WebSockets.

Quick reference for Storybook 8+ with CSF 3, TypeScript, and interaction testing.

This is a deprecated HTML feature. See: Using the application cache (developer.mozilla.org)

Web Speech API: SpeechSynthesis and SpeechSynthesisUtterance reference.

JSDoc: JavaScript documentation comments, tags, and type annotations.

Messages can be anything that can be serialized into JSON (objects, arrays, strings, numbers, booleans). See: structured clone

npm: javascript reference and quick guide.

Months are zero-indexed (eg, January is 0).

Non-2xx responses are still successful requests. Use another function to turn them to errors.

Quick reference for CoffeeScript - a little language that compiles into JavaScript with Ruby-inspired syntax and significant whitespace.

[GSAP](https://gsap.com/) (GreenSock Animation Platform) is a professional-grade JavaScript animation library for building high-performance animations that work in every major browser.

A quick reference for how the `this` keyword works in every JavaScript context — global, functions, methods, classes, arrow functions, and event handlers.

[KnockoutJS](https://knockoutjs.com/) is a standalone JavaScript MVVM library with declarative bindings, automatic UI refresh, dependency tracking, and templating.

Meteor is a full-stack JavaScript platform for developing modern web and mobile applications. It includes a key set of technologies for building connected-client reactive applications.

Tracking.js is a lightweight browser computer vision library (~7KB) providing color tracking, face/eye/mouth detection, and feature detection. Note: This library is unmaintained since 2016.

Quick reference for JavaScript's async/await syntax for handling asynchronous operations with cleaner, more readable code than traditional Promise chains.

Embedded JavaScript templating - Simple, fast templating language for Node.js with plain JavaScript syntax.

A quick overview of new JavaScript features in ES2015, ES2016, ES2017, ES2018 and beyond.

ES2018 (ES9) features: async iteration, object rest/spread, Promise.finally(), RegExp improvements

Electron is a framework for building cross-platform desktop applications using JavaScript, HTML, and CSS. Build native apps with web technologies.

Joi is a powerful schema description language and data validator for JavaScript. Validate objects, arrays, strings, numbers and more with an expressive fluent API.

Quick reference for Lerna - a fast, modern build system for managing and publishing JavaScript/TypeScript monorepos, now maintained by Nx.

SQL-friendly ORM for Node.js built on Knex.js. Supports PostgreSQL, MySQL, and SQLite3.

[Vue.js](https://vuejs.org/) is an open-source Model–view–viewmodel JavaScript framework for building user interfaces and single-page applications.

**Deprecated:** this guide targets an old version of Vuej.js (v1.0.28). See the [updated Vue.js cheatsheet](vue) for new versions.

[101](https://www.npmjs.com/package/101) is a JavaScript library for dealing with immutable data in a functional manner.

Angular 2 is the TypeScript-based rewrite of AngularJS, introducing components, modules, and a new template syntax.

Angular 4 introduced animations as a separate package, HttpClient (in 4.3), enhanced *ngIf with else/as syntax, and Renderer2.

Angular 5 made HttpClient the default, introduced the build optimizer, RxJS pipeable operators, forms updateOn, and i18n pipe improvements.

Angular CLI (@angular/cli) is the official command-line tool for creating, developing, building, and testing Angular applications.

In controller you call with parameter and will use promises to return data from server.

Backbone.js: quick reference for common patterns and api methods.

Blessed: quick reference for common patterns and api methods.

Bookshelf.js: quick reference for common patterns and api methods.

Browserify is a bundler for JavaScript.

Browsersync: quick reference for common patterns and api methods.

var cli = require('commander');

Quick reference for [Deku](https://www.npmjs.com/package/deku), a minimal virtual DOM library. **Deprecated:** This is for Deku v1. See [deku](./deku) for a more updated cheatsheet.

Quick reference for [Deku](https://www.npmjs.com/package/deku), a minimal virtual DOM library.

Express.js: quick reference for common patterns and api methods.

Fastify lets you create HTTP servers in Node.js with good performance. This guide targets fastify v0.28.x.

Gulp: quick reference for common patterns and api methods.

[Harvey.js](http://harvesthq.github.io/harvey/) helps you build responsive interfaces.

Immutable.js: quick reference for common patterns and api methods.

Enable these options to not throw errors in these conditions.

Koa is a web framework for Node.js.

Middleman 3: quick reference for common patterns and api methods.

This is a mocha template that loads js/css from cdn.

Use [blanket](https://npmjs.com/package/blanket) for easy coverage reporting for Mocha JavaScript tests.

Mocha.js: quick reference for common patterns and api methods.

Mocha.js TDD interface: quick reference for common patterns and api methods.

[Modella](https://www.npmjs.com/package/modella) allows you to create simple models in JavaScript. This is a guide on basic usage of Modella in CoffeeScript.

<script src='//cdnjs.cloudflare.com/ajax/libs/modernizr/2.6.2/modernizr.min.js'></script>

This parses the given date using the given format. Returns a moment object.

Nock: quick reference for common patterns and api methods.

Nopt: quick reference for common patterns and api methods.

Parsimmon: quick reference for common patterns and api methods.

Polyfill.io is a service that serves JavaScript polyfills.

Q.js: quick reference for common patterns and api methods.

A quick reference for the [QUnit](https://yarnpkg.com/package/qunit) testing library in JavaScript.

Ractive is a UI library for JavaScript.

A quick reference to [Ramda](https://ramdajs.com/), a practical functional programming library for JavaScript with automatic currying, data-last arguments, and immutability.

Riot is a UI library for JavaScript.

[Rollup](https://rollupjs.org/) Rollup is a module bundler for JavaScript which compiles small pieces of code into something larger and more complex, such as a library or application.

Sequelize is an ORM for JavaScript.

Sinon-chai: quick reference for common patterns and api methods.

Spine is an MVC framework for JavaScript.

[Stencil](https://github.com/ionic-team/stencil) is a compiler for web components made by the Ionic team. This guide targets Stencil v0.0.5.

Superagent: quick reference for common patterns and api methods.

Tape: quick reference for common patterns and api methods.

Three.js is a JavaScript 3D library for creating and displaying 3D graphics in the browser using WebGL/WebGPU. This covers the most commonly used API patterns.

TypeScript is just like ES2015 with type-checking. All ES2015 (classes, etc) should work.

Underscore-string: quick reference for common patterns and api methods.

Universal JS module loader: quick reference for common patterns and api methods.

Quick reference for [Velocity.js](http://velocityjs.org), a fast animation engine that works with and without jQuery.

Virtual-dom: quick reference for common patterns and API methods.

Vows: quick reference for common patterns and api methods.

Quick reference for [Vuex](https://vuex.vuejs.org), the state management library for Vue.js. Covers Vuex 4 (Vue 3). Note: [Pinia](https://pinia.vuejs.org) is now recommended for new projects.

This is a very basic "getting started with Webpack" guide for use with [Webpack](https://webpack.js.org) v3. This doesn't cover all features, but it should get you started in understanding the config file format.

[weinre](https://www.npmjs.com/package/weinre) is a remote Web inspector. Note that it has been deprecated since 2016.

Yargs: quick reference for common patterns and api methods.

[Zombie](http://zombie.js.org/) is a full-stack testing solution for Node.js.

jQuery CDN: quick reference for common patterns and api methods.

js-model: quick reference for common patterns and api methods.

A small guide into installing [jscoverage](https://npmjs.com/package./jscoverage). Also see [mocha-blanket](./mocha-blanket).

All options are optional, but it's recommended you set string and boolean at least.

Quick reference for [w2ui](https://w2ui.com), a lightweight JavaScript UI library with grid, layout, sidebar, toolbar, tabs, form, and popup widgets. Covers v2.0 (no jQuery dependency).

[Camp](https://github.com/espadrine/sc/) is a Node.js web server framework. This guide targets Camp v17.x.

[Gremlins](https://github.com/marmelab/gremlins.js) is a JavaScript library to do "monkey-testing" by providing random user input (clicks, scrolls, and so on).

Handlebars.js: quick reference for common patterns and api methods.

Note: This cheatsheet may be a little outdated. Also see the Jest cheatsheet. Jest uses Jasmine, and therefore has similar API.

[meow](https://npmjs.com/package/meow) is the easiest way to write command line apps for Node.js.

[Parsley](http://parsleyjs.org/doc/) provides frontend form validation.

[ShellJS](https://github.com/shelljs/shelljs) is a portable (Windows/Linux/OS X) implementation of Unix shell commands on top of the Node.js API.

Sinon: quick reference for common patterns and api methods.

Also see the promise cheatsheet and Bluebird.js API (github.com).

[co](https://github.com/tj/co) allows you to use generators to manage async flow.

Expect is a library for assertions in tests.

jQuery: quick reference for common patterns and api methods.

Chai.js: quick reference for common patterns and api methods.

Most of what you need to do is to simply add annotations to function arguments!

A quick overview to [Jest](https://facebook.github.io/jest/), a test framework for Node.js. This guide targets Jest v20.

Works for both arrays and objects.

Pug: quick reference for common patterns and api methods.

[RxJS](https://rxjs.dev/) is a reactive programming library for composing asynchronous and event-based programs using observable sequences. This guide covers RxJS v7.x.

These options are available for yarn install.

Angular 6 introduced ng update/add CLI commands, Angular Elements, RxJS 6, tree-shakable providers, and library support.

Jade/Pug template engine syntax. Renamed to Pug in 2016.

Choo is a 4kb functional framework for building single-page applications with minimal API and real DOM diffing.

Quick reference for D3.js v7+ — JavaScript library for data-driven DOM manipulation and data visualization.

[MobX](https://mobx.js.org/) is a simple, scalable, signal-based state management library. It makes state management simple by transparently applying functional reactive programming.

[NProgress](https://ricostacruz.com/nprogress/) is a slim progress bar for Ajax applications, inspired by Google, YouTube, and Medium. Created by Rico Sta. Cruz.

Create a CNAME file with your domain on it.

Jekyll: quick reference and cheatsheet.

Jekyll for GitHub pages: quick reference and cheatsheet.

Queries are used on all commands (bal, reg, etc). (docs)

Ledger CSV format: ledger cli commands and accounting patterns.

Ledger examples: ledger cli commands and accounting patterns.

Ledger format: ledger cli commands and accounting patterns.

Ledger periods: ledger cli commands and accounting patterns.

Ledger queries: ledger cli commands and accounting patterns.

Ledger CLI: ledger cli commands and accounting patterns.

Emmet is a markup language for expanding CSS rules into HTML

Haml: syntax reference and formatting guide.

Kramdown is a Markdown parser in Ruby.

Place this at the beginning of the file.

ReStructuredText is a markup language for writing documents.

Tomdoc: syntax reference and formatting guide.

Yaml: syntax reference and formatting guide.

Markdown: syntax reference and formatting guide.

Textile: syntax reference and formatting guide.

Quick reference for Liquid, the safe, customer-facing template language by Shopify. Used in Shopify themes and Jekyll sites.

AppleScript: quick reference and cheatsheet.

OS X: quick reference and cheatsheet.

Disable mouse acceleration with this one weird trick.

Node.js API: node.js apis, modules, and patterns.

Quick reference to the [Node.js path API](https://nodejs.org/api/path.html).

assert: node.js apis, modules, and patterns.

fs.readFile('file.txt', function(err, data) { .. });

process: node.js apis, modules, and patterns.

Node.js streams: node.js apis, modules, and patterns.

Highlighted lines are required.

A simple CLI tool for ensuring that a given Node.js script runs continuously (i.e. forever). Community-maintained process manager for Node.js applications.

Node.js body parsing middleware for Express. Parses incoming request bodies (JSON, URL-encoded, raw, text) before your handlers. Built into Express 4.16.0+.

package.json manifest reference for Node.js projects. Define metadata, dependencies, scripts, entry points, and npm package configuration.

Quick reference for Twig - a modern, fast, and secure template engine for PHP used by Symfony, Drupal, and many PHP applications.

Quick reference for Doctrine ORM with PHP 8+ attributes syntax

Laravel is a PHP web application framework with expressive, elegant syntax. This cheatsheet covers Laravel 11.x/12.x - routing, Eloquent ORM, Blade templates, validation, and Artisan commands.

Quick reference for PHP - a popular server-side scripting language for web development covering PHP 7+ and PHP 8 modern features.

Quick reference for PHP 7.0-7.4 new features including type declarations, operators, arrow functions, and more.

Quick reference for Phalcon - a high-performance PHP framework delivered as a C extension for maximum speed with minimal overhead.

Quick reference for Symfony 8.0 - PHP web application framework with MVC architecture, Doctrine ORM, Twig templating, and powerful CLI tools.

Jinja: quick reference and cheatsheet.

Mako: quick reference and cheatsheet.

Python: quick reference and cheatsheet.

Jinja2 template engine for Python. Used in Flask, Ansible, and many other frameworks.

Side-by-side comparison of Python 2 and Python 3 syntax differences for migration and compatibility.

Quick reference guide for Django 5.1 - Python web framework for building web applications with clean, pragmatic design.

Quick reference guide for Flask, the Python micro web framework. Covers routing, templates, blueprints, and more.

Arel is an SQL abstraction library built into Ruby on Rails.

Rails: rails conventions, helpers, and configuration.

Rails controllers: rails conventions, helpers, and configuration.

Field names will be prefixed with post (the class name), and values will be derived from this object (eg, f.text_field :name from @post.name).

distanceoftimeinwords(Time.now, project.end_date) #=> 3 hours

Rails i18n: rails conventions, helpers, and configuration.

$ rails generate migration RemovePartNumberFromProducts part_number:string

Rails models: rails conventions, helpers, and configuration.

Generate a Rails Engine plugin:

in config/environments/development.rb:

Routes: rails conventions, helpers, and configuration.

Apollo Client: React hooks for GraphQL queries, mutations, subscriptions, and caching.

Create action creators in flux standard action format.

Flux is an architecture for building client-side web applications.

A quick reference to the [prop-types](https://www.npmjs.com/package/prop-types) package for runtime type checking in React components.

**Deprecated:** this guide targets an old version of React (v0.14). See the [updated React cheatsheet](react) for new versions.

[Relay](https://relay.dev/) is Meta's GraphQL client for React with ahead-of-time compilation, data masking, and automatic cache updates. This guide covers Relay v16+.

CSS-in-JS library for React and React Native. Write component-scoped CSS with template literals, dynamic theming, and TypeScript support.

Enzyme lets you write unit tests for React components. This guide covers Enzyme 3.x.

Shallow wrapping doesn't descend down to sub-components.

[Redux Saga](https://redux-saga.js.org/) is a middleware for managing side effects in Redux using generator functions. This guide covers redux-saga v1.x.

A store is made from a reducer function, which takes the current state, and

[Gatsby.js](https://www.gatsbyjs.com/) is a React-based static site generator with a GraphQL data layer, plugin ecosystem, and support for SSG, DSG, and SSR rendering modes.

[React Native](https://reactnative.dev/) lets you build native mobile apps using React. This guide covers React Native 0.83+ with Expo and React Navigation 7.

[React Router](https://reactrouter.com/) is the standard routing library for React. This guide covers React Router v7 (latest) with notes for v6 users.

Unstated is a minimal React state management library built on the Context API. Uses Container classes with familiar setState(). Note: Unmaintained since ~2019; see unstated-next for a hooks-based successor.

[React](https://reactjs.org/) is a JavaScript library for building user interfaces. This guide targets React v15 to v16.

Allows you to filter listings by a certain scope.

bundle # same as bundle install

Minitest: ruby syntax, methods, and idioms reference.

RSpec is a Ruby library for testing.

Rake: ruby syntax, methods, and idioms reference.

RSpec is a Ruby library for testing. rspec-rails is its Rails integration.

Quick reference to some features of the Ruby programming language.

Quick reference to the [new features in Ruby 2.1](https://www.ruby-lang.org/).

A quick reference to common [rubygems](https://rubygems.org) CLI commands.

Trigger reflexes without writing any javascript with the data-reflex attribute.

[rbenv](https://github.com/rbenv/rbenv) lets you manage installations of multiple Ruby versions.

Goby's language design is based on Ruby language's, slim and shaped up. Differences in syntax between them is very small.

Quick reference for Sinatra, the lightweight Ruby DSL for creating web applications with minimal effort.

Chunky PNG: api reference and common usage patterns.

server = DO::Server.new('srv1', 'srv1.domain.local', 'root', :key =>

FFaker: api reference and common usage patterns.

Machinist is a fixture management library for Ruby.

[PSD.rb](https://github.com/layervault/psd.rb) parses Photoshop documents in Ruby.

Packs are a specification for an extensible packaging system to help modularize Ruby applications.

Pry is a runtime development console for Ruby.

Sequel is a database toolkit for Ruby.

rack-test: api reference and common usage patterns.

Works in a controller or a view.

Ronn generates Man pages. See [ronn(1)](https://rtomayko.github.io/ronn/ronn.1.html), [ronn-format(7)](https://rtomayko.github.com/ronn/ronn-format.7.html). Also see it on GitHub: [rtomayko/ronn](httpss://github.com/rtomayko/ronn).

You can use parentheses, brackets, or none at all.

Factory Bot is a helper for writing factories for Ruby tests. It was previously known as Factory Girl. For older versions, use FactoryGirl instead of FactoryBot.

Capybara: api reference and common usage patterns.

Projectionist: vim commands, motions, and configuration reference.

Then press options (if available), then a delimiter.

Vim digraphs: vim commands, motions, and configuration reference.

Use ft=help to preview it, and ft=text to edit it.

Vim-Unite: vim commands, motions, and configuration reference.

Vim-rails: vim commands, motions, and configuration reference.

Vimscript functions: vim commands, motions, and configuration reference.

command! YoFunctionHere call s:YoFunctionHere()

[Tabular](https://github.com/godlygeek/tabular) is a Vim script for text alignment.

Vim is a very efficient text editor. This reference was made for Vim 8.0.

You can either put this in a script (script.vim) and run it (:source script.vim), or you can type the commands individually in normal mode as :let and :echo.

[Vim](https://www.vim.org/) is a very efficient text editor. This reference was made for Vim 8.0.

AGENTS.md is an open specification - a "README for AI coding agents" - providing a predictable location for project-specific context and instructions. Used by 60k+ open-source projects and supported by all major AI coding tools.

[Absinthe](http://absinthe-graphql.org/) allows you to write GraphQL servers in Elixir.

AngularDart is the Dart port of Angular, sharing the same architecture but using Dart instead of TypeScript. Used at Google for products like Google Ads.

A quick reference to common [Apache Cordova](https://cordova.apache.org/) commands.

Bolt is available as a package for most platforms. See installing bolt

CIDR: quick reference and cheatsheet.

Caskroom index cheatsheet with commands, syntax, and examples.

This is a reference of styles that you can use on Devhints cheatsheets. How meta! You can refer to this when contributing your own cheatsheets to the [GitHub repo](https://github.com/rstacruz/cheatsheets/).

Claude Code is an AI-powered CLI assistant for software engineering tasks. This reference covers the most commonly used commands and features.

Quick reference for Clojure - a dynamic, functional Lisp dialect on the JVM with immutable data structures and a powerful concurrency model.

Command line stuff cheatsheet with commands, syntax, and examples.

Devise is a flexible authentication

Divshot was a static hosting platform.

Quick reference for F# - a functional-first language on .NET with type inference, pattern matching, and seamless C# interop.

Run figlet with -f <font> to use a font. Part 1 of 2 (fonts 3-d through ivrit).

Run figlet with -f <font> to use a font. Part 2 of 2 (fonts jazmine through wideterm).

Firebase cheatsheet with commands, syntax, and examples.

[iframe-sandbox]: https://developer.mozilla.org/en-US/docs/HTML/Element/iframe#attr-sandbox

Food delivery numbers & sites for top restaurant chains in Metro Manila. For numbers outside Metro Manila, check their websites.

Freenode cheatsheet with commands, syntax, and examples.

Duplicate the layer twice. Perform these in each layer:

Google Analytics cheatsheet with commands, syntax, and examples.

Short snippets on using [Google Webfonts](https://google.com/fonts) in a web page.

GraphQL queries look the same for both single items or lists of items.

HCL (HashiCorp Configuration Language) is the declarative language used by Terraform for infrastructure as code. This cheatsheet covers syntax, expressions, functions, meta-arguments, and Terragrunt extensions.

WebDAV is an extension of HTTP that allows clients to perform remote Web content authoring operations. It provides a framework for users to create, change and move documents on a server. It adds the f

A quick reference for common [Imagemagick](https://www.imagemagick.org) commands and switches.

Modern Java cheatsheet covering Java 17+ features. Focuses on current best practices and modern syntax. Legacy patterns (pre-Java 8) are intentionally excluded.

Jujutsu (jj) - Git-compatible version control with automatic snapshots, no staging area, and first-class conflicts. Modern DVCS for Git users seeking better UX.

Quick reference for Julia - a high-performance dynamic language for scientific computing with multiple dispatch and a sophisticated type system.

Less.js cheatsheet with commands, syntax, and examples.

Licenses cheatsheet with commands, syntax, and examples.

Linux cheatsheet with commands, syntax, and examples.

Lua cheatsheet with commands, syntax, and examples.

Make for assets cheatsheet with commands, syntax, and examples.

Quick reference for MoonScript - a dynamic scripting language that compiles to Lua with classes, comprehensions, and CoffeeScript-inspired syntax.

Pacman is the package manager for Arch Linux and its derivatives.

Use perl to search and replace across many files.

This is an example nginx configuration.

PlantUML is a markup language for creating diagrams.

[Premailer](https://github.com/premailer/premailer/) is a Ruby library that inlines CSS into HTML.

Here's an example of a possible error reply.

Quick reference for Rust - a systems programming language focused on safety, speed, and concurrency with zero-cost abstractions and memory safety without garbage collection.

Saucelabs cheatsheet with commands, syntax, and examples.

[Siege](https://www.joedog.org/siege-home/) is an HTTP and HTTPS load testing tool.

SimpleForm cheatsheet with commands, syntax, and examples.

Spreadsheet functions cheatsheet with commands, syntax, and examples.

Quick reference for Swift - Apple's modern, safe, and fast programming language for iOS, macOS, watchOS, tvOS, and server-side development.

aptitude search mysql # Look for something

Unicode symbols cheatsheet with commands, syntax, and examples.

Vainglory: game items, builds, and strategy reference.

A quick reference to the [ZNC](https://znc.bg) IRC bouncer's common commands.

Quick reference for Zed - a high-performance, multiplayer code editor built in Rust with built-in AI assistance and real-time collaboration.

Needed for Adhoc & Appstore builds.

Screen resolutions cheatsheet with commands, syntax, and examples.

Watchman cheatsheet with commands, syntax, and examples.

For multiline patterns (m flag), ^ and $ will act as start and end of line.

Given a version number MAJOR.MINOR.PATCH:

Used by Ruby, UNIX date, and many more.

Official kubectl plugin manager for discovering, installing, and managing kubectl plugins.

[MarkoJS](https://markojs.com/) is a compiler-based UI framework created by eBay with built-in streaming SSR, partial hydration, and an HTML-first syntax.

SolidJS is a reactive JavaScript framework for building user interfaces. Fine-grained reactivity, no Virtual DOM, components run once. ~7KB gzipped.

Fast Kubernetes namespace switching tool. Switch namespaces with interactive fuzzy search, previous namespace toggle, and force-set for non-existent namespaces.

The strftime format is the standard date formatting for UNIX. It's used in C, Ruby, and more.

Quick reference for APEX - Salesforce's strongly typed, object-oriented programming language for the Force.com platform.

Amazon Elastic Kubernetes Service (EKS) - Fully managed Kubernetes on AWS. Reference for EKS architecture, node types (EC2/Fargate), IAM/RBAC, networking, storage, add-ons, and troubleshooting common issues.

Astro is a modern web framework for building fast, content-focused websites with zero JS by default and Islands Architecture for interactive components.

Brainfuck is a minimalist esoteric programming language created by Urban Müller in 1993. With only 8 commands, it's Turing-complete yet intentionally difficult to use—perfect for understanding computational fundamentals.

Fast all-in-one JavaScript runtime with bundler, test runner, and package manager. Drop-in replacement for Node.js with native TypeScript support.

Quick reference for modern C++ (C++11 through C++23) covering STL containers, smart pointers, move semantics, and templates.

Quick reference for Common Lisp development with SBCL and SLIME integration.

Quick reference for Crystal - a statically-typed, compiled language with Ruby-like syntax that compiles to native code via LLVM.

Quick reference for Dart - a client-optimized language for fast apps on any platform and the primary language for Flutter development.

Quick reference for Deno - a modern JavaScript/TypeScript runtime with secure defaults, built-in tooling, and native TypeScript support.

Elm is a functional programming language for building reliable web applications with no runtime exceptions. Features the Elm Architecture (Model-Update-View), strong static typing, and friendly compiler errors.

Quick reference for Erlang - a functional language built for massively concurrent, fault-tolerant, distributed systems with hot code swapping.

Groovy is a powerful, optionally typed and dynamic language for the JVM with static compilation capabilities. This guide covers Groovy syntax, operators, closures, and Gradle DSL.

Quick reference for Haskell - a purely functional programming language with strong static typing, lazy evaluation, and powerful type inference.

Helm is the package manager for Kubernetes. This guide covers Helm v4 (latest), v3, and migration from v2. Quick reference for install, upgrade, rollback, debugging, hooks, and troubleshooting.

Quick reference for JSON Schema Draft 2020-12 - validate JSON documents with declarative schemas

Quick reference for JSON:API v1.1 specification - a standardized format for building APIs in JSON

Quick reference for Kubernetes architecture, API versions, resource groups, and distribution management with kOps.

Quick reference for Lit - Simple, fast, web components library. Build encapsulated, reusable components with reactive properties, declarative templates, and scoped styles.

[Next.js](https://nextjs.org/) is a React framework for building full-stack web applications. It provides server-side rendering, static generation, file-based routing, and built-in optimizations.

Quick reference for Nim - a statically typed compiled systems programming language with Python-like syntax, metaprogramming capabilities, and multiple backend targets (C/C++/JS).

Quick reference for Perl - a high-level, interpreted language renowned for text processing, regular expressions, and system administration.

[Polymer 2](https://polymer-library.polymer-project.org/2.0/docs/) is a library for building web components using the Web Components standards. Note: Polymer is in maintenance mode — [Lit](https://lit.dev) is recommended for new projects.

Fast 3kB alternative to React with the same modern API. Preact provides the thinnest possible Virtual DOM abstraction on top of the real DOM.

Qwik is a resumable web framework with ~1KB initial JavaScript load. No hydration needed - apps resume where server left off.

Quick reference for R - a language and environment for statistical computing, data analysis, and visualization widely used in data science.

Quick reference for ASP.NET Core Razor template syntax - the server-side markup language for creating dynamic web pages with C#.

ReasonML is a syntax extension for OCaml with first-class React support and JavaScript interop. This guide covers syntax, types, patterns, and interop.

Quick reference for Scala - a multi-paradigm language blending object-oriented and functional programming on the JVM.

Smalltalk is a pure object-oriented programming language where everything is an object and computation happens through message passing. Its syntax is famously minimal—it fits on a postcard.

Solidity is a statically-typed, object-oriented programming language for writing smart contracts on Ethereum and EVM-compatible blockchains.

Spring Boot is an opinionated framework for building production-ready Spring applications with minimal configuration.

Svelte is a radical new approach to building user interfaces. Instead of using techniques like virtual DOM diffing, Svelte writes code that surgically updates the DOM when the state of your app changes.

Terragrunt is a thin wrapper for Terraform/OpenTofu that provides extra tools for keeping configurations DRY, working with multiple modules, and managing remote state.

Quick reference for VBA (Visual Basic for Applications) - the programming language for Microsoft Office automation, macros, and Excel scripting.

Fast, modern frontend build tool with native ESM, instant HMR, and optimized production builds. Vite provides a lightning-fast dev experience for modern web projects.

Quick reference for Zig programming language - a general-purpose systems language focused on robustness, optimal performance, and maintainability with compile-time execution and seamless C interop.

Official CLI tool for Amazon EKS. Automates cluster creation, management, and operations using declarative YAML configs and CLI commands.

High-performance RPC framework using Protocol Buffers over HTTP/2 with cross-language support

Quick reference for iOS development with SwiftUI and UIKit frameworks. Covers state management, navigation, networking, and iOS-specific APIs.

Quick reference for iOS-specific development with Swift. Covers SwiftUI, UIKit interop, state management, navigation, data persistence, and iOS APIs. For Swift language syntax, see the Swift cheatsheet.

Command-line tool for Kubernetes. Deploy apps, inspect resources, debug pods, view logs, and manage clusters. Complete reference for kubectl commands, troubleshooting workflows, and common error fixes.

Fast way to switch between Kubernetes clusters and contexts.