Install nodejs v20 on Debian and Ubuntu based distributions

step 1 : Download and import the Nodesource GPG key

sudo apt-get update
sudo apt-get install -y ca-certificates curl gnupg
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://deb.nodesource.com/gpgkey/nodesource-repo.gpg.key | sudo gpg --dearmor -o /etc/apt/keyrings/nodesource.gpg

step 2 : Create deb repository

NODE_MAJOR=20
echo "deb [signed-by=/etc/apt/keyrings/nodesource.gpg] https://deb.nodesource.com/node_$NODE_MAJOR.x nodistro main" | sudo tee /etc/apt/sources.list.d/nodesource.list

optional: here we are installing nodejs v20 but if you want to install v18 change NODE_MAJOR=18 in above command. Similarly if you want to install nodejs v16 then change NODE_MAJOR=16.

step 3 : Run Update and Install

sudo apt-get update
sudo apt-get install nodejs -y

congratulations you just installed nodejs

To uninstall nodejs

sudo apt-get purge nodejs &&\
rm -r /etc/apt/sources.list.d/nodesource.list &&\
rm -r /etc/apt/keyrings/nodesource.gpg

NodeSource provides binary distributions of Node.js; complete installation instructions can be found here. The instructions have been copied below for your reference. Instructions are the same for updating to the latest version.

Run once:

sudo apt-get update
sudo apt-get install -y ca-certificates curl gnupg
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://deb.nodesource.com/gpgkey/nodesource-repo.gpg.key | sudo gpg --dearmor -o /etc/apt/keyrings/nodesource.gpg

Run whenever you want to change the major version of Node.js:

NODE_MAJOR=20
echo "deb [signed-by=/etc/apt/keyrings/nodesource.gpg] https://deb.nodesource.com/node_$NODE_MAJOR.x nodistro main" | sudo tee /etc/apt/sources.list.d/nodesource.list
sudo apt-get update
sudo apt-get install nodejs -y

Prior to August 2023: Previously versions of this answer involved the use of a series of setup_XX.x scripts that you'd run to install/update Node.js:

curl -fsSL https://deb.nodesource.com/setup_current.x | sudo -E bash -
sudo apt-get install -y nodejs

But as @eis pointed out, these scripts are no longer supported. To see the previous answers, please look at the edit history for this answer.