npx(1) -- execute npm package binaries

SYNOPSIS

npx [--package|-p <package>] [--cache <path>] [--userconfig <path>] [-c <string>] [--shell|-s <string>] [--no-install] [--shell-auto-fallback [<shell>]] [--ignore-existing] [--version|-v] [--] <command>[@version] [command-arg]...

INSTALL

npm install -g npx

DESCRIPTION

Executes <command> either from a local node_modules/.bin, or from a central cache, installing any packages needed in order for <command> to run.

By default, npx will check whether <command> exists in $PATH, or in the local project binaries, and execute that. If <command> is not found, it will be installed prior to execution.

Unless a --package option is specified, npx will try to guess the name of the binary to invoke depending on the specifier provided. All package specifiers understood by npm may be used with npx, including git specifiers, remote tarballs, local directories, or scoped packages.

An optional @version may be appended to specify the package version required, which defaults to latest only if <command> is not in the path. If the command is already present and no explicit version specifier was requested, the existing command will be used.

If a version specifier is included, or if --package is used, npx will ignore the version of the package in the current path, if it exists. This can also be forced with the --ignore-existing flag.

• -p, --package <package> - define the package to be installed. This defaults to the value of <command>. This is only needed for packages with multiple binaries if you want to call one of the other executables, or where the binary name does not match the package name. If this option is provided <command> will be executed as-is, without interpreting @version if it's there. Multiple --package options may be provided, and all the packages specified will be installed.

• --no-install - If passed to npx, it will only try to run <command> if it already exists in the current path or in $prefix/node_modules/.bin. It won't try to install missing commands.

• --cache <path> - set the location of the npm cache. Defaults to npm's own cache settings.

• --userconfig <path> - path to the user configuration file to pass to npm. Defaults to whatever npm's current default is.

• -c <string> - Execute <string> inside a shell. For unix, this will be /bin/sh -c <string>. For Windows, it will be cmd.exe /d /s /c <string>. Only the first item in <string> will be automatically used as <command>. Any others must use -p.

• --shell <string> - The shell to invoke the command with, if any. Defaults to false.

• --shell-auto-fallback [<shell>] - Generates shell code to override your shell's "command not found" handler with one that calls npx. Tries to figure out your shell, or you can pass its name (either bash, fish, or zsh) as an option. See below for how to install.

• --ignore-existing - If this flag is set, npx will not look in $PATH, or in the current package's node_modules/.bin for an existing version before deciding whether to install. Binaries in those paths will still be available for execution, but will be shadowed by any packages requested by this install.

• -v, --version - Show the current npx version.

EXAMPLES

Running a project-local bin

$ npm i -D webpack
$ npx webpack ...

One-off invocation without local installation

$ npm rm webpack
$ npx webpack -- ...
$ cat package.json
...webpack not in "devDependencies"...

Invoking a command from a github repository

$ npx github:piuccio/cowsay
...or...
$ npx git+ssh://my.hosted.git:cowsay.git#semver:^1
...etc...

Execute a full shell command using one npx call w/ multiple packages

$ npx -p lolcatjs -p cowsay -c 'echo "foo" | cowsay | lolcatjs'
...
 _____
< foo >
 -----
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\
                ||----w |
                ||     ||

SHELL AUTO FALLBACK

You can configure npx to run as your default fallback command when you type something in the command line but the command is not found. This includes installing packages that were not found in the local prefix either.

Currently, zsh, bash, and fish are supported. You can access these completion scripts using npx --shell-auto-fallback <shell>.

To install permanently, add the relevant line below to your ~/.bashrc, ~/.zshrc, ~/.config/fish/config.fish, or as needed. To install just for the shell session, simply run the line.

You can optionally pass through --no-install when generating the fallback to prevent it from installing packages if the command is missing.

For Bash:

$ source <(npx --shell-auto-fallback bash)

For Zsh:

$ source <(npx --shell-auto-fallback zsh)

For Fish:

$ source (npx --shell-auto-fallback fish | psub)

ACKNOWLEDGEMENTS

Huge thanks to Kwyn Meagher for generously donating the package name in the main npm registry. Previously npx was used for a Tessel board Neopixels library, which can now be found under npx-tessel.

AUTHOR

Written by Kat Marchan.

REPORTING BUGS

Please file any relevant issues on Github.

LICENSE

This work is released by its authors into the public domain under CC0-1.0. See LICENSE.md for details.

SEE ALSO

• npm(1)
• npm-run-script(1)
• npm-config(7)