Install and Use the Node Package Manager (NPM) on Linux

The Node Package Manager (NPM) is the most widely-used package manager for JavaScript projects and includes Node.js by default. This guide walks you through installing NPM and getting started using it on your Linux system.

What is NPM?

NPM is the default package manager for Node.js projects. NPM includes a command-line tool (CLI) that give you access to the NPM package registry . The registry stores the numerous JavaScript packages made available through the NPM CLI, along with their metadata. The NPM website gives you an easy way to search for JavaScript packages and read information about them. The package.json file that is generated by the NPM CLI helps you manage project dependencies. It also ensures consistent project installations across environments.

NPM vs Yarn

The Yarn package manager has become a popular alternative to NPM. Both NPM and Yarn use the NPM registry to get packages and package information, and the commands in each tool are pretty similar.

One advantage to NPM is that it is the default package manager for Node.js. If you have Node.js installed on your system, you automatically have access to NPM. This means that once you have Node.js installed, you immediately have access to all the functionality available through the NPM package registry.

NPM is also the most popular Node.js package manager. With that popularity comes a wide range of coverage. You are more likely to find Node.js projects and examples that use NPM than you are to find ones using Yarn.

Yarn was originally designed to address performance and security concerns in NPM. And while Yarn still outshines NPM in terms of speed, NPM has made vast security improvements that put it about even with Yarn.

How to Install or Update NPM

The steps in this section show you how to install NPM along with Node.js. It also gives you methods for updating your NPM installation.

How to Install NPM

Since NPM is packaged with Node.js, you just need to install Node.js. The installation path recommended by NPM is using a the Node Version Manager (nvm). This version manager helps you avoid permissions issues and version conflicts with NPM packages. To install nvm follow the steps in our How to Install and Use the Node Version Manager NVM guide.

Using nvm, you can install the current stable version of Node.js, and its accompanying version of NPM using the following command:

nvm install node

To verify your NPM installation, check for the installed npm version.

npm -v

7.20.3

How to Update NPM

When working with nvm to manage your Node.js versions, updating your NPM version requires that you update your Node.js version. To make sure you are on the latest version of NPM, use NVM’s install command to install the current stable Node.js version.

nvm install node

Then, tell NVM to use the latest version.

nvm use node

If you want to update NPM, without updating Node.js, use nvm’s dedicated command.

nvm install-latest-npm

How to Install Packages with NPM

The sections that follow show you how to install and use NPM packages.

Most often, you install NPM packages for a specific project. Use commands below to create an example NPM project to follow along with this guide.

Create a new directory for the example project and move into the new directory.

mkdir ~/example-app
cd ~/example-app

Initialize the new NPM project.

npm init

NPM prompts you for information about your project. Use the defaults for this example. The result is an initial package.json file representing your project.

Install Packages to a Project

NPM provides two main ways for installing specific packages to your project.

• You can install a specific package with NPM’s install command. In the example below, NPM installs the latest stable version of the package. The example installs the Express web application framework.

  npm install express
  

• Alternatively, you can explicitly specify the package version you want installed on your system.

  npm install express@4.17.1
  

  You can even specify a version range for the package you want to be installed. Place the version expression between quotes, and precede the version number with the comparison operator you want to use. You can use multiple version constraints, separating them with spaces.

  npm install express@">=4.1.0 <4.17.1"
  

  The above command installs the latest available version of the Express JS package that is equal to or greater than 4.1.0 and less than 4.17.1.

Package.json

The npm init command creates a package.json file in the project’s base directory. Any packages installed in the project are reflected in this file. The package.json is a reflection of your project’s dependency structure.

The file below is an example package.json that results from the basic npm install express command (from the above section).

File: package.json

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{ "name": "example-app", "version": "1.0.0", "description": "", "main": "index.js", "scripts": { "test": "echo \"Error: no test specified\" && exit 1" }, "author": "", "license": "ISC", "dependencies": { "express": "^4.17.1" } }

Notice that the express package is listed under dependencies. The ^ indicates that a package version compatible with version 4.17.1 must be installed for this project.

Take a look at NPM’s package.json documentation, specifically the dependencies section for more information about the syntax used for parsing package versions. The same syntax can be used when specifying a version, or a version range, for the install command.

Install Dependencies for an Existing Project

You may come across an existing project, with its own package.json, that you want to get up and running. Typically, you first need to install the project’s dependencies. You can do this by running the install command from that base directory without specifying a package. For example:

npm install

NPM uses the project’s package.json to determine which packages are needed and which versions of those packages are compatible with the project. If the project has a package-lock.json, NPM also uses that to further ensure compatibility with the dependencies that get installed.

Install Packages Globally

You may want to install some packages globally. Packages installed in this way are available anywhere on the system, not just within a particular project.

You can accomplish this with NPM’s global (-g) flag, as shown below:

npm install -g express

You can also use the -g option with the commands in the next two sections. This option allows you to uninstall and update global packages.

How to Remove Packages with NPM

You can uninstall an NPM package with the uninstall command.

npm uninstall express

The uninstall command updates the package.json to reflect that the project no longer depends on the uninstalled package.

File: package.json

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{ "name": "example-app", "version": "1.0.0", "description": "", "main": "index.js", "scripts": { "test": "echo \"Error: no test specified\" && exit 1" }, "author": "", "license": "ISC" }

How to Update Packages with NPM

You can use the command below to update all of a project’s packages to their latest compatible versions.

npm update

NPM references the version constraints given in the project’s package.json file to ensure that updates do not contradict your project’s specified version.

More Information

You may wish to consult the following resources for additional information on this topic. While these are provided in the hope that they will be useful, please note that we cannot vouch for the accuracy or timeliness of externally hosted materials.

• NPM Docs
• NPM dependencies