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. Installed packages are stored 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. Flags that appear after the name are passed 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), automatically installing into a global shared cache if not installed in node_modules.

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