zx

Zx is a Node.js library from Google that makes it easy and enjoyable to write shell scripts using JavaScript instead of Bash. The problem it solves is a common frustration: Bash is great for simple automation tasks, but as scripts grow more complex — needing conditionals, loops, data processing, error handling, and async operations — Bash becomes cumbersome. JavaScript is a much richer language for that logic, but running shell commands from Node.js traditionally requires verbose, low-level code to manage child processes, handle pipes, escape arguments, and deal with output buffers.

Zx bridges that gap by providing a clean, minimal API on top of Node.js's child process system. Its core feature is the tagged template literal $, which lets you write shell commands inline in your JavaScript file using backticks. For example, await $git branch --show-current` runs the git command and gives you its output as a JavaScript string. Arguments are automatically escaped to prevent security issues, and the output can be used immediately in your JavaScript logic. Multiple shell commands can be run in parallel using Promise.all, just like any other asynchronous JavaScript operation.

Beyond the core $` operator, Zx bundles a set of commonly-needed utilities: functions for reading user input, colored terminal output, fetching URLs, reading and writing files, and working with YAML and TOML. It also handles argument parsing for building CLI tools.

A developer would use Zx when they need to write automation scripts — build processes, deployment pipelines, file processing tasks, developer tooling — and they would rather work in JavaScript/TypeScript than Bash, Python, or Ruby.

The tech stack is JavaScript and TypeScript running on Node.js, Bun, or Deno. Available as an npm package.