Generally speaking, loading arbitrary data from a URL into a root shell session is not a good idea and I wish people would stop peddling it as a solution for everything - "Please just run this script I'm sending you, and also while we're at it - I have a bridge you'd probably be interested in purchasing".

As an alternative, here's the "Ubuntu Way" of doing the same, where you can see how the system is being updated and know what repositories and what keys are added to your system configuration:

curl https://deb.nodesource.com/gpgkey/nodesource.gpg.key | sudo apt-key add -

sudo apt-add-repository "deb https://deb.nodesource.com/node_7.x $(lsb_release -sc) main"

sudo apt-get update

sudo apt-get install nodejs

This is for the latest (at time of writing) Nodejs version 7. Other versions can also be gotten with a simple change to the repo URL - consult nodesource.com documentation for details.

Node.js v4.x:

# Using Ubuntu

curl -sL https://deb.nodesource.com/setup_4.x | sudo -E bash -

sudo apt-get install -y nodejs



# Using Debian, as root

curl -sL https://deb.nodesource.com/setup_4.x | bash -

apt-get install -y nodejs

source: https://github.com/nodesource/distributions#debinstall

If you want to update inside npm, you can use the n command:

sudo npm cache clean -f

sudo npm install -g n

sudo n stable

This installs the n package which you can use to switch NodeJS-Versions and uses it. Comparison to the alternative NVM and command options are at SO. There is also a blog post.

curl -sL https://deb.nodesource.com/setup_0.12 | sudo bash -

# Then install with:

sudo apt-get install -y nodejs

Here you can find more info: Node.js v0.12, io.js, and the NodeSource Linux Repositories

For version 5.x According to PPA:

apt-get remove --purge nodejs npm

curl -sL https://deb.nodesource.com/setup_5.x | sudo -E bash -

apt-get install nodejs

To install NPM,

sudo apt-get install npm

Then for Node,

sudo npm cache clean -f

sudo npm install -g n

sudo n 0.xx.x  // here is the version what you want.. 

This command will install node based on your version you want..

NVM (Node Version manager)

https://github.com/creationix/nvm

NVM installs both the latest stable node and npm for you

curl https://raw.githubusercontent.com/creationix/nvm/master/install.sh | sh

source ~/.nvm/nvm.sh

nvm install --lts

nvm use --lts

npm --version

Now test it out with a dummy package:

npm install --global vaca

vaca

Since the sourcing has to be done for every new shell, you will probably want to add the following to your .bashrc:

f="$HOME/.nvm/nvm.sh"

if [ -r "$f" ]; then

  . "$f" &>'/dev/null'

  nvm use --lts &>'/dev/null'

fi

Advantages:

• allows you to use multiple versions of Node and without sudo




• is analogous to Ruby RVM and Python Virtualenv, widely considered best practice in Ruby and Python communities




• downloads a pre-compiled binary where possible, and if not it downloads the source and compiles one for you

We can easily switch node versions with:

nvm install 0.9.0

nvm install 0.9.9

nvm use 0.9.0

node --version

#v0.9.0

nvm use 0.9.9

node --version

#v0.9.9

Tested in Ubuntu 17.10.

You can install latest version very easily using below instruction.

curl -sL https://deb.nodesource.com/setup_7.x | sudo -E bash -

Vesion 7.x is the latest version of node.

sudo apt-get install nodejs

Above line will install nodejs.

sudo apt-get install build-essential

This will install essential modules for nodejs to run properly.

Now check whether nodejs installed correctly at your end

nodejs -v

This will return installed nodejs version.

npm -v

This will return installed npm version. Hope it helps....

Source : link will show you how to install nodejs using some other methods as well.

Node.js is available as a snap package in all currently supported versions of Ubuntu. Specific to Node.js, developers can choose from one of the currently supported releases and get regular automatic updates directly from NodeSource. Node.js versions 6, 8, 9, 10, 11 and 12 are currently available, with the Snap Store being updated within hours, or minutes of a Node.js release.

Node can be installed with a single command, for example:

sudo snap install node --classic --channel 11/stable 

The node snap can be accessed by the command node, for example:

$ node -v  

v11.5.0

An up-to-date version of npm will installed as part of the node snap. npm should be run outside of the node repl, in your normal shell. After installing the node snap run the following command to enable npm update checking:

sudo chown -R $USER:$(id -gn $USER) /home/your-username/.config

Replace your-username in the above command with your own username. Then run npm -v to check if the version of npm is up-to-date. As an example I checked that npm was up-to-date, checked the version of an already installed package named yarn with the command npm list yarn and then updated the existing yarn package to the latest version with the command npm update yarn

Users can switch between versions of Node.js at any time without needing to involve additional tools like nvm (Node Version Manager), for example:

sudo snap refresh node --channel=11/stable

Users can test bleeding-edge versions of Node.js that can be installed from the latest edge channel which is currently tracking Node.js version 12 by switching with:

sudo snap switch node --edge

This approach is only recommended for those users who are willing to participate in testing and bug reporting upstream.

Node.js LTS Schedule

Release LTS Status  Codename    LTS Start       Maintenance Start Maintenance End

6.x     Active      Boron       2016-10-18      April 2018        April 2019

7.x     No LTS              

8.x     Active      Carbon      2017-10-31      April 2019        December 2019

9.x     No LTS              

10.x    Active      Dubnium     October 2018    April 2020        April 2021  

11.x    No LTS                                  2019-04-01        2019-06-30

12.x    No LTS                  2019-10-22      2021-04-01        2022-04-01

For Ubuntu 15.10 you can download the .deb package form packages.ubuntu.com

node --version

v4.2.3

Just a spin-off of the answer by @23W (accepted answer).

This is just the contents of the script, just to avoid doing curl to root shell.

curl -s https://deb.nodesource.com/gpgkey/nodesource.gpg.key | sudo apt-key add -

echo "deb https://deb.nodesource.com/node_6.x $(lsb_release -c -s) main" | sudo tee /etc/apt/sources.list.d/nodesource.list

echo "deb-src https://deb.nodesource.com/node_6.x $(lsb_release -c -s) main" | sudo tee -a /etc/apt/sources.list.d/nodesource.list



sudo apt-get update

sudo apt-get install -y nodejs

Download nodejs from https://nodejs.org/

To install from a terminal:

cd /usr/local

tar --strip-components 1 -xJf ~/Downloads/node-v4.4.5-linux-x64.tar.xz

//Download

cd ~/Downloads

wget https://nodejs.org/dist/v4.4.5/node-v4.4.5-linux-x64.tar.xz



//Install

cd /usr/local

tar --strip-components 1 -xJf ~/Downloads/node-v4.4.5-linux-x64.tar.xz



//Verify

node -v

npm version

Source

My favorite way to install latest nodejs and npm is using the installation binaries archive provided on nodejs' website.

This might quickly become your new favorite way too. Works like a charm. It involves 1 download and 1 command. Done. NO errors [the multiple times I've done this]. Didn't need to uninstall existing stuff beforehand.

Installing nodejs via Binaries

At first remove the installed version: (if exists)

sudo apt-get remove nodejs

Download

https://nodejs.org/en/download/stable/

Download Linux Binaries.

• I had to extract the tar.xz to a folder and then re-compress as tar.gz

Install

sudo tar -C /usr/local --strip-components 1 -xzf /path/to/downloaded/tar/node-vYOURVERSION-linux-x64.tar.gz

Verify

node -v

npm --version

Source

http://www.thegeekstuff.com/2015/10/install-nodejs-npm-linux/

Video Explanation

NVM is very simple to install and allows you to easily switch node versions. From the github repository:

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

downloads and runs the installation script

nvm ls-remote

to see the available versions. Say you want to install version 8.9.4

nvm install 8.9.4

and you're done.

To install another version and use it (say 9.6.1)

nvm install 9.6.1

nvm alias default 9.6.1

This approach allows you easily delete Node.JS, keep different versions and provide the commands to all the system users.

Download the stable version of Node.JS, uncompress it, and move it into /opt.

In case you wish to install different versions, you can rename the folder according to its version code:

/opt/node/6.9.1

Since only root can change files in /opt/, if you don't wish to call invoke sudo every time you need to modify a file, change the group permission:

chgrp adm -R /opt/node/6.9.1

Then create file /etc/profile.d/node.sh if the following content:

export NODE_ENV=/opt/node/6.9.1

export CPLUS_INCLUDE_PATH=${NODE_ENV}/include

export C_INCLUDE_PATH=${NODE_ENV}/include

export LD_LIBRARY_PATH=${NODE_ENV}/lib

export MANPATH=${NODE_ENV}/share/man:${MANPATH}



export PATH=${NODE_ENV}/bin:$PATH

Logout and login and X-Window will reload all profile configurations.

If you had a previous versions installed, to avoid library conflicts run:

npm cache clean

Update Package Manager

sudo apt-get update

Adding NodeJS PPAs

sudo apt-get install python-software-properties

curl -sL https://deb.nodesource.com/setup_6.x | sudo -E bash -

Installing NodeJS and NPM

sudo apt-get install nodejs

Here, I Wrote a Complete Blog post about Installing NodeJS and NPM in Ubuntu.
Click Here to Read

Updating Package Manager

sudo apt-get update

Adding PPA

sudo apt-get install python-software-properties



curl -sL https://deb.nodesource.com/setup_7.x | sudo -E bash -

Installing NodeJS and NPM

sudo apt-get install nodejs

For Reference : Installing NodeJS in Ubuntu - WebCheerz