While developing linux services with Node.js I found myself switching between various versions of Node.js and eventually it just made sense to create a Bash script to manage the process of switching between versions.

nodejs-install github repository

Rather than hunt for the needed download and manually installing all that is required is to run a simple command...

sudo ./nodejs-install.sh install -v 10.15.3

As demonstrated in the following video, the process is simple. Use git to clone the nodejs-install repository, then execute the install script with root permissions while passing the install command and the version option. The Node.js install package will be downloaded and setup for global use. If the package was previously installed the download is skipped and the selected version is set as the global default. In the demonstration I install an older version of Node.js, test the installed version, then install a newer version of Node.js, again test the installed version, and finally run the install command for the older version again which will skip the download and when complete I again test the installed version.

Auto Download

After validating the version on the download page, the script checks to see if the requested version is alredy installed. If the version is already installed then the download step is automatically skipped and the existing install is configured as the system default.

      # install nodejs
      function InstallNodeJS()
      {
        IsRoot
        # get version details in array (filename version platform architecture)
        local version=($(VersionAvailable "$NODE_PLATFORM" "$NODE_ARCHITECTURE"))
        if [[ -z "$version" ]]; then exit 1; fi
        local node_version="${version[1]}" # may differ if search was in "latest"
        local node_file="${version[0]}"
        local node_install_dir=$(VersionPath $node_version)
        local node_download_path="${NODE_SELECTED_WEB_PATH}/v${NODE_VERSION}/${node_file}"

        mkdir -p "$INSTALL_PATH"
        cd $INSTALL_PATH

        # get node package if not installed
        if [ ! -d $node_install_dir ]; then
          wget "$node_download_path" -O "$node_file"
          local wgetreturn=$?
          if [[ $wgetreturn -ne 0 ]]; then
            Die "Download $node_download_path failed"
          fi
          # extract
          tar xf "$node_file"
          # remove tar
          rm -f "$node_file"
        fi
        if [ $(UsingAlternatives) ]; then
          InstallAlternatives "$INSTALL_PATH/$node_install_dir" "$node_version"
        else
          InstallSymlinks "$INSTALL_PATH/$node_install_dir"
        fi
        echo "Install complete."
      }
    

Symlinks or Alternatives

Some linux distributions include the alternatives command to manage symbolic links but the script is designed to manage the symbolic links when alternatives is not available.

      # check if system uses alternatives
      function UsingAlternatives() {
        command -v update-alternatives
        if [ $? -eq 0 ]; then
          true
        else
          false
        fi
      }

      # install in alternatives
      function InstallAlternatives()
      {
        local node_install_path=$1;
        local node_version=$2
        local priority=`echo $node_version | sed 's/[\.v]//g'`
        update-alternatives --install /usr/bin/node node "$node_install_path/bin/node" "$priority"
        update-alternatives --set node "$node_install_path/bin/node"
        update-alternatives --install /usr/bin/npm npm "$node_install_path/bin/npm" "${priority}"
        update-alternatives --set npm "$node_install_path/bin/npm"
        if [ -f "$node_install_path/bin/npx" ]; then
          update-alternatives --install /usr/bin/npx npx "$node_install_path/bin/npx" "${priority}"
          update-alternatives --set npx "$node_install_path/bin/npx"
        fi
      }


      # install as symlink
      function InstallSymlinks()
      {
        local node_install_path=$1;
        ln -sf "$node_install_path/bin/node" "$BIN_PATH/node"
        ln -sf "$node_install_path/bin/npm" "$BIN_PATH/npm"
        if [ -f "$node_install_path/bin/npx" ]; then
          ln -sf "$node_install_path/bin/npx" "$BIN_PATH/npx"
        fi
      }