# zx — Write Better Shell Scripts in JavaScript

> A tool by Google for writing shell scripts using JavaScript with built-in support for command execution, pipes, and popular CLI utilities like cd, fetch, and chalk.

## Install

Save as a script file and run:

# zx — Write Better Shell Scripts in JavaScript

## Quick Use
```bash
npm install zx
# Create script.mjs:
# #!/usr/bin/env zx
# await $`ls -la`
# await $`git status`
chmod +x script.mjs
npx zx script.mjs
```

## Introduction
zx is a tool from Google that makes writing shell scripts in JavaScript painless. It provides useful wrappers around child_process, adds built-in support for template literal shell commands, and bundles common utilities so you can replace Bash scripts with type-safe, cross-platform JavaScript.

## What zx Does
- Executes shell commands via tagged template literals using the `$` function
- Bundles globby, chalk, fs-extra, fetch, and YAML parsing out of the box
- Supports top-level await and runs .mjs files directly
- Provides pipe operators and stdin/stdout stream handling between commands
- Offers a REPL mode for interactive shell scripting in JavaScript

## Architecture Overview
zx wraps Node.js child_process.spawn under the hood, parsing tagged template literals into shell commands that are executed in a spawned process. Each `$` call returns a ProcessPromise that resolves with stdout and stderr. Pipes are chained by connecting the stdout stream of one process to the stdin of another, all managed through native Node.js streams.

## Self-Hosting & Configuration
- Install globally with `npm install -g zx` or per-project with `npm install zx`
- Scripts use the `.mjs` extension for native ES module support
- Set `$.shell` to change the default shell (e.g., `/bin/bash`, `powershell.exe`)
- Use `$.verbose = false` to suppress command echoing in production scripts
- Configure `$.cwd` to set the working directory for all subsequent commands

## Key Features
- Tagged template literal syntax for shell commands with automatic escaping
- Built-in utilities: chalk for colors, globby for globs, fetch for HTTP
- Cross-platform execution works on Linux, macOS, and Windows
- TypeScript support with full type definitions included
- Markdown script support: write scripts inside fenced code blocks in .md files

## Comparison with Similar Tools
- **ShellJS** — synchronous, older API; zx is async-first with modern ES module syntax
- **Execa** — focused on process execution; zx adds shell scripting ergonomics and built-in utilities
- **Bash** — not cross-platform and lacks type safety; zx runs on any OS with Node.js
- **Bun Shell** — Bun-specific; zx works with any Node.js runtime
- **ts-node scripts** — requires more boilerplate; zx scripts are concise and run directly

## FAQ
**Q: Can I use TypeScript with zx?**
A: Yes. zx supports .ts files natively and ships with TypeScript definitions.

**Q: Does zx handle errors like set -e in Bash?**
A: Yes. By default, a non-zero exit code throws a ProcessOutput error that you can catch with try/catch.

**Q: Can I use zx without installing it globally?**
A: Yes. Use `npx zx script.mjs` to run scripts without global installation.

**Q: Is zx suitable for production automation?**
A: Yes. It is widely used for CI/CD scripts, build automation, and DevOps tooling where JavaScript is preferred over Bash.

## Sources
- https://github.com/google/zx
- https://google.github.io/zx/

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Source: https://tokrepo.com/en/workflows/asset-efcb8d69
Author: Script Depot