bunx

Use bunx to auto-install and run packages from npm. It's Bun's equivalent of npx or yarn dlx.

bunx cowsay "Hello world!"

Packages can declare executables in the "bin" field of their package.json. These are known as package executables or package binaries.

{
  // ... other fields
  "name": "my-cli",
  "bin": {
    "my-cli": "dist/index.js"
  }
}

These executables are commonly plain JavaScript files marked with a shebang line naming the program that should run them. The following file runs with node.

#!/usr/bin/env node

console.log("Hello world!");

Run these executables with bunx:

bunx my-cli

As with npx, bunx checks for a locally installed package first, then falls back to auto-installing it from npm. bunx stores installed packages in Bun's global cache for future use.

Arguments and flags

To pass additional command-line flags and arguments through to the executable, place them after the executable name.

bunx my-cli --foo bar

Shebangs

By default, Bun respects shebangs. If an executable is marked with #!/usr/bin/env node, Bun spins up a node process to execute the file. To run the executable with Bun's runtime instead, pass the --bun flag.

bunx --bun my-cli

The --bun flag must occur before the executable name. bunx passes flags that appear after the name through to the executable.

bunx --bun my-cli # good
bunx my-cli --bun # bad

Package flag

--package <pkg> or -p <pkg> - Run a binary from a specific package. Useful when the binary name differs from the package name:

bunx -p renovate renovate-config-validator
bunx --package @angular/cli ng

To force a script to always run with Bun, give it a bun shebang.

#!/usr/bin/env bun

Usage

bunx [flags] <package>[@version] [flags and arguments for the package]

Execute an npm package executable (CLI). If the package isn't installed in node_modules, Bun installs it into a global shared cache.

Flags

Examples

# Run Prisma migrations
bunx prisma migrate

# Format a file with Prettier
bunx prettier foo.js

# Run a specific version of a package
bunx uglify-js@3.14.0 app.js

# Use --package when binary name differs from package name
bunx -p @angular/cli ng new my-app

# Force running with Bun instead of Node.js, even if the executable contains a Node shebang
bunx --bun vite dev foo.js