sudo apt update
sudo apt upgrade

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

root@junyang:~# curl https://raw.githubusercontent.com/creationix/nvm/master/install.sh | bash
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 15916  100 15916    0     0  82895      0 --:--:-- --:--:-- --:--:-- 83329
=> Downloading nvm from git to '/root/.nvm'
=> Initialized empty Git repository in /root/.nvm/.git/
=> Compressing and cleaning up git repository

=> nvm source string already in /root/.bashrc
=> bash_completion source string already in /root/.bashrc
=> Close and reopen your terminal to start using nvm or run the following to use it now:

export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"  # This loads nvm
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"  # This loads nvm bash_completion

export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"  # This loads nvm
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"  # This loads nvm bash_completion

source ~/.bashrc

nvm --version