xref: /third_party/node/deps/npm/docs/content/commands/npm-exec.md (revision 1cb0ef41)

---
title: npm-exec
section: 1
description: Run a command from a local or remote npm package
---

### Synopsis

```bash
npm exec -- <pkg>[@<version>] [args...]
npm exec --package=<pkg>[@<version>] -- <cmd> [args...]
npm exec -c '<cmd> [args...]'
npm exec --package=foo -c '<cmd> [args...]'

alias: x
```

### Description

This command allows you to run an arbitrary command from an npm package
(either one installed locally, or fetched remotely), in a similar context
as running it via `npm run`.

Run without positional arguments or `--call`, this allows you to
interactively run commands in the same sort of shell environment that
`package.json` scripts are run.  Interactive mode is not supported in CI
environments when standard input is a TTY, to prevent hangs.

Whatever packages are specified by the `--package` option will be
provided in the `PATH` of the executed command, along with any locally
installed package executables.  The `--package` option may be
specified multiple times, to execute the supplied command in an environment
where all specified packages are available.

If any requested packages are not present in the local project
dependencies, then a prompt is printed, which can be suppressed by
providing either `--yes` or `--no`. When standard input is not a TTY or a
CI environment is detected, `--yes` is assumed. The requested packages are
installed to a folder in the npm cache, which is added to the `PATH`
environment variable in the executed process.

Package names provided without a specifier will be matched with whatever
version exists in the local project.  Package names with a specifier will
only be considered a match if they have the exact same name and version as
the local dependency.

If no `-c` or `--call` option is provided, then the positional arguments
are used to generate the command string.  If no `--package` options
are provided, then npm will attempt to determine the executable name from
the package specifier provided as the first positional argument according
to the following heuristic:

- If the package has a single entry in its `bin` field in `package.json`,
  or if all entries are aliases of the same command, then that command
  will be used.
- If the package has multiple `bin` entries, and one of them matches the
  unscoped portion of the `name` field, then that command will be used.
- If this does not result in exactly one option (either because there are
  no bin entries, or none of them match the `name` of the package), then
  `npm exec` exits with an error.

To run a binary _other than_ the named binary, specify one or more
`--package` options, which will prevent npm from inferring the package from
the first command argument.

### `npx` vs `npm exec`

When run via the `npx` binary, all flags and options *must* be set prior to
any positional arguments.  When run via `npm exec`, a double-hyphen `--`
flag can be used to suppress npm's parsing of switches and options that
should be sent to the executed command.

For example:

```
$ npx foo@latest bar --package=@npmcli/foo
```

In this case, npm will resolve the `foo` package name, and run the
following command:

```
$ foo bar --package=@npmcli/foo
```

Since the `--package` option comes _after_ the positional arguments, it is
treated as an argument to the executed command.

In contrast, due to npm's argument parsing logic, running this command is
different:

```
$ npm exec foo@latest bar --package=@npmcli/foo
```

In this case, npm will parse the `--package` option first, resolving the
`@npmcli/foo` package.  Then, it will execute the following command in that
context:

```
$ foo@latest bar
```

The double-hyphen character is recommended to explicitly tell npm to stop
parsing command line options and switches.  The following command would
thus be equivalent to the `npx` command above:

```
$ npm exec -- foo@latest bar --package=@npmcli/foo
```

### Configuration

#### `package`

* Default:
* Type: String (can be set multiple times)

The package or packages to install for [`npm exec`](/commands/npm-exec)



#### `call`

* Default: ""
* Type: String

Optional companion option for `npm exec`, `npx` that allows for specifying a
custom command to be run along with the installed packages.

```bash
npm exec --package yo --package generator-node --call "yo node"
```



#### `workspace`

* Default:
* Type: String (can be set multiple times)

Enable running a command in the context of the configured workspaces of the
current project while filtering by running only the workspaces defined by
this configuration option.

Valid values for the `workspace` config are either:

* Workspace names
* Path to a workspace directory
* Path to a parent workspace directory (will result in selecting all
  workspaces within that folder)

When set for the `npm init` command, this may be set to the folder of a
workspace which does not yet exist, to create the folder and set it up as a
brand new workspace within the project.

This value is not exported to the environment for child processes.

#### `workspaces`

* Default: null
* Type: null or Boolean

Set to true to run the command in the context of **all** configured
workspaces.

Explicitly setting this to false will cause commands like `install` to
ignore workspaces altogether. When not set explicitly:

- Commands that operate on the `node_modules` tree (install, update, etc.)
will link workspaces into the `node_modules` folder. - Commands that do
other things (test, exec, publish, etc.) will operate on the root project,
_unless_ one or more workspaces are specified in the `workspace` config.

This value is not exported to the environment for child processes.

#### `include-workspace-root`

* Default: false
* Type: Boolean

Include the workspace root when workspaces are enabled for a command.

When false, specifying individual workspaces via the `workspace` config, or
all workspaces via the `workspaces` flag, will cause npm to operate only on
the specified workspaces, and not on the root project.

This value is not exported to the environment for child processes.

### Examples

Run the version of `tap` in the local dependencies, with the provided
arguments:

```
$ npm exec -- tap --bail test/foo.js
$ npx tap --bail test/foo.js
```

Run a command _other than_ the command whose name matches the package name
by specifying a `--package` option:

```
$ npm exec --package=foo -- bar --bar-argument
# ~ or ~
$ npx --package=foo bar --bar-argument
```

Run an arbitrary shell script, in the context of the current project:

```
$ npm x -c 'eslint && say "hooray, lint passed"'
$ npx -c 'eslint && say "hooray, lint passed"'
```

### Workspaces support

You may use the [`workspace`](/using-npm/config#workspace) or
[`workspaces`](/using-npm/config#workspaces) configs in order to run an
arbitrary command from an npm package (either one installed locally, or fetched
remotely) in the context of the specified workspaces.
If no positional argument or `--call` option is provided, it will open an
interactive subshell in the context of each of these configured workspaces one
at a time.

Given a project with configured workspaces, e.g:

```
.
+-- package.json
`-- packages
   +-- a
   |   `-- package.json
   +-- b
   |   `-- package.json
   `-- c
       `-- package.json
```

Assuming the workspace configuration is properly set up at the root level
`package.json` file. e.g:

```
{
    "workspaces": [ "./packages/*" ]
}
```

You can execute an arbitrary command from a package in the context of each of
the configured workspaces when using the
[`workspaces` config options](/using-npm/config#workspace), in this example
we're using **eslint** to lint any js file found within each workspace folder:

```
npm exec --ws -- eslint ./*.js
```

#### Filtering workspaces

It's also possible to execute a command in a single workspace using the
`workspace` config along with a name or directory path:

```
npm exec --workspace=a -- eslint ./*.js
```

The `workspace` config can also be specified multiple times in order to run a
specific script in the context of multiple workspaces. When defining values for
the `workspace` config in the command line, it also possible to use `-w` as a
shorthand, e.g:

```
npm exec -w a -w b -- eslint ./*.js
```

This last command will run the `eslint` command in both `./packages/a` and
`./packages/b` folders.

### Compatibility with Older npx Versions

The `npx` binary was rewritten in npm v7.0.0, and the standalone `npx`
package deprecated at that time.  `npx` uses the `npm exec`
command instead of a separate argument parser and install process, with
some affordances to maintain backwards compatibility with the arguments it
accepted in previous versions.

This resulted in some shifts in its functionality:

- Any `npm` config value may be provided.
- To prevent security and user-experience problems from mistyping package
  names, `npx` prompts before installing anything.  Suppress this
  prompt with the `-y` or `--yes` option.
- The `--no-install` option is deprecated, and will be converted to `--no`.
- Shell fallback functionality is removed, as it is not advisable.
- The `-p` argument is a shorthand for `--parseable` in npm, but shorthand
  for `--package` in npx.  This is maintained, but only for the `npx`
  executable.
- The `--ignore-existing` option is removed.  Locally installed bins are
  always present in the executed process `PATH`.
- The `--npm` option is removed.  `npx` will always use the `npm` it ships
  with.
- The `--node-arg` and `-n` options are removed.
- The `--always-spawn` option is redundant, and thus removed.
- The `--shell` option is replaced with `--script-shell`, but maintained
  in the `npx` executable for backwards compatibility.

### A note on caching

The npm cli utilizes its internal package cache when using the package
name specified.  You can use the following to change how and when the
cli uses this cache. See [`npm cache`](/commands/npm-cache) for more on
how the cache works.

#### prefer-online

Forces staleness checks for packages, making the cli look for updates
immediately even if the package is already in the cache.

#### prefer-offline

Bypasses staleness checks for packages.  Missing data will still be
requested from the server. To force full offline mode, use `offline`.

#### offline

Forces full offline mode. Any packages not locally cached will result in
an error.

#### workspace

* Default:
* Type: String (can be set multiple times)

Enable running a command in the context of the configured workspaces of the
current project while filtering by running only the workspaces defined by
this configuration option.

Valid values for the `workspace` config are either:

* Workspace names
* Path to a workspace directory
* Path to a parent workspace directory (will result to selecting all of the
  nested workspaces)

This value is not exported to the environment for child processes.

#### workspaces

* Alias: `--ws`
* Type: Boolean
* Default: `false`

Run scripts in the context of all configured workspaces for the current
project.

### See Also

* [npm run-script](/commands/npm-run-script)
* [npm scripts](/using-npm/scripts)
* [npm test](/commands/npm-test)
* [npm start](/commands/npm-start)
* [npm restart](/commands/npm-restart)
* [npm stop](/commands/npm-stop)
* [npm config](/commands/npm-config)
* [npm workspaces](/using-npm/workspaces)
* [npx](/commands/npx)