Node install on Ubuntu using NVM (Node Version Manager)

How To Install Using NVM

An alternative to installing Node.js through apt is to use a specially designed tool called nvm, which stands for "Node.js version manager". Rather than working at the operating system level, nvm works at the level of an independent directory within your home directory. This means that you can install multiple, self-contained versions of Node.js without affecting the entire system.

Controlling your environment with nvm allows you to access the newest versions of Node.js and retain and manage previous releases. It is a different utility from apt-get, however, and the versions of Node.js that you manage through it are distinct from the distro-stable version of Node.js available from the Ubuntu repositories.

To start off, we'll need to get the software packages from our Ubuntu repositories that will allow us to build source packages. The nvm script will leverage these tools to build the necessary components:

sudo apt-get update

sudo apt-get install build-essential libssl-dev

Once the prerequisite packages are installed, you can pull down the nvm installation script from the project's GitHub page. The version number may be different, but in general, you can download it with curl:

curl -sL https://raw.githubusercontent.com/creationix/nvm/v0.33.8/install.sh -o install_nvm.sh

And inspect the installation script with nano:

nano install_nvm.sh

Run the script with bash:

bash install_nvm.sh

It will install the software into a subdirectory of your home directory at ~/.nvm. It will also add the necessary lines to your ~/.profile file to use the file.

To gain access to the nvm functionality, you'll need to log out and log back in again, or you can source the ~/.profile file so that your current session knows about the changes:

source ~/.profile

Now that you have nvm installed, you can install isolated Node.js versions.

To find out the versions of Node.js that are available for installation, you can type:

nvm ls-remote

Output
...
         v8.5.0
         v8.6.0
         v8.7.0
         v8.8.0
         v8.8.1
         v8.9.0   
         v8.9.1   
         v8.9.2   
         v8.9.3   
->      v8.9.4   (Latest LTS: Carbon)        

As you can see, the newest LTS version at the time of this writing is v8.9.4. You can install that by typing:

nvm install 8.9.4

Usually, nvm will switch to use the most recently installed version. You can explicitly tell nvm to use the version we just downloaded by typing:

nvm use 8.9.4

When you install Node.js using nvm, the executable is called node. You can see the version currently being used by the shell by typing:

node -v

Output
v8.9.4

If you have multiple Node.js versions, you can see what is installed by typing:

nvm ls

If you wish to default one of the versions, you can type:

nvm alias default 8.9.4

This version will be automatically selected when a new session spawns. You can also reference it by the alias like this:

nvm use default

Each version of Node.js will keep track of its own packages and has npm available to manage these.

You can have npm install packages to the Node.js project's ./node_modules directory by using the normal format. For example, for the express module:

npm install express

If you'd like to install it globally (making it available to the other projects using the same Node.js version), you can add the -g flag:

npm install -g express

This will install the package in:

~/.nvm/node_version/lib/node_modules/package_name

Installing globally will let you run the commands from the command line, but you'll have to link the package into your local sphere to require it from within a program:

npm link express

You can learn more about the options available to you with nvm by typing:

nvm help

Removing Node.js

You can uninstall Node.js using apt-get or nvm, depending on the version you want to target. To remove the distro-stable version, you will need to work with the apt-get utility at the system level.

To remove the distro-stable version, type the following:

sudo apt-get remove nodejs

This command will remove the package and retain the configuration files. These may be of use to you if you intend to install the package again at a later point. If you don’t want to save the configuration files for later use, however, then run the following:

sudo apt-get purge nodejs

This will uninstall the package and remove the configuration files associated with it. 
As a final step, you can remove any unused packages that were automatically installed with the removed package:

sudo apt-get autoremove

To uninstall a version of Node.js that you have enabled using nvm, first determine whether or not the version you would like to remove is the current active version:

nvm current

If the version you are targeting is not the current active version, you can run:

nvm uninstall node_version

This command will uninstall the selected version of Node.js.

If the version you would like to remove is the current active version, you must first deactive nvm to enable your changes:

nvm deactivate

You can now uninstall the current version using the uninstall command above, which will remove all files associated with the targeted version of Node.js except the cached files that can be used for reinstallment.