Docs restructuring (#2638)

* Restructure

* Update nav

* Reorg

* Reshuffle ecosystem pages

* Split up runtime/runtime

* Back to runtime/index

* Fix issue

* Split up runtime/index

* Add Writing Tests page

* Prettier matcher table

* More updates

1 files changed, 40 insertions, 13 deletions

diff --git a/docs/cli/run.md b/docs/cli/run.md
index 133f3e1ec..7a5f8e9d2 100644
--- a/docs/cli/run.md
+++ b/docs/cli/run.md
@@ -1,31 +1,38 @@
 The `bun` CLI can be used to execute JavaScript/TypeScript files, `package.json` scripts, and [executable packages](https://docs.npmjs.com/cli/v9/configuring-npm/package-json#bin).
 
-## Running a file
+<!-- ## Speed -->
+
+<!--
+Performance sensitive APIs like `Buffer`, `fetch`, and `Response` are heavily profiled and optimized. Under the hood Bun uses the [JavaScriptCore engine](https://developer.apple.com/documentation/javascriptcore), which is developed by Apple for Safari. It starts and runs faster than V8, the engine used by Node.js and Chromium-based browsers. -->
+
+## Run a file
 
 {% callout %}
 Compare to `node <file>`
 {% /callout %}
 
-Bun can execute `.js`, `.jsx`, `.ts`, and `.tsx` files. Every file is transpiled to vanilla JavaScript by Bun's fast native transpiler before being executed. For details on Bun's runtime, refer to the [Bun runtime](/docs/runtime) documentation.
+Use `bun run` to execute a source file.
 
-```ts#foo.ts
-import { z } from "zod";
-
-const schema = z.string()
-const result = schema.parse("Billie Eilish");
-console.log(result);
+```bash
+$ bun run index.js
 ```
 
-To run a file in Bun:
+Bun supports TypeScript and JSX out of the box. Every file is transpiled on the fly by Bun's fast native transpiler before being executed.
 
 ```bash
-$ bun foo.ts
-Billie Eilish
+$ bun run index.js
+$ bun run index.jsx
+$ bun run index.ts
+$ bun run index.tsx
 ```
 
-If no `node_modules` directory is found in the working directory or above, Bun will abandon Node.js-style module resolution in favor of the `Bun module resolution algorithm`. Under Bun-style module resolution, all packages are _auto-installed_ on the fly into a [global module cache](/docs/cli/install#global-cache). For full details on this algorithm, refer to [Runtime > Modules](/docs/runtime/modules).
+The "naked" `bun` command is equivalent to `bun run`.
 
-## Running a package script
+```bash
+$ bun index.tsx
+```
+
+## Run a `package.json` script
 
 {% note %}
 Compare to `npm run <script>` or `yarn <script>`
@@ -80,3 +87,23 @@ quickstart scripts:
 ```
 
 Bun respects lifecycle hooks. For instance, `bun run clean` will execute `preclean` and `postclean`, if defined. If the `pre<script>` fails, Bun will not execute the script itself.
+
+## Environment variables
+
+Bun automatically loads environment variables from `.env` files before running a file, script, or executable. The following files are checked, in order:
+
+1. `.env.local` (first)
+2. `NODE_ENV` === `"production"` ? `.env.production` : `.env.development`
+3. `.env`
+
+To debug environment variables, run `bun run env` to view a list of resolved environment variables.
+
+## Performance
+
+Bun is designed to start fast and run fast.
+
+Under the hood Bun uses the [JavaScriptCore engine](https://developer.apple.com/documentation/javascriptcore), which is developed by Apple for Safari. In most cases, the startup and running performance is faster than V8, the engine used by Node.js and Chromium-based browsers. It's transpiler and runtime are written in Zig, a modern, high-performance language. On Linux, this translates into startup times [4x faster](https://twitter.com/jarredsumner/status/1499225725492076544) than Node.js.
+
+{% image src="/images/bun-run-speed.jpeg" caption="Bun vs Node.js vs Deno running Hello World" /%}
+
+<!-- If no `node_modules` directory is found in the working directory or above, Bun will abandon Node.js-style module resolution in favor of the `Bun module resolution algorithm`. Under Bun-style module resolution, all packages are _auto-installed_ on the fly into a [global module cache](/docs/cli/install#global-cache). For full details on this algorithm, refer to [Runtime > Modules](/docs/runtime/modules). -->