Rake task for nvm - node version manager

nvm.rake

namespace :nvm do
  desc "Load nvm and the node environment variables"

  def file_or_symlink_exists?(path_to_file)
    File.exist?(path_to_file) || File.symlink?(path_to_file)
  end

  desc "Load node if nvm is already installed but not on the path"
  task :load_node do
    sh "/bin/bash -c '. ~/.nvm/nvm.sh'"
    system(". ~/.nvm/nvm.sh")
    nodefile = `which nodejs`
    nodeversion = `node -v`
    puts "The node version is: #{nodeversion}"
    puts "The node file is: #{nodefile}"
    output = File.exist?('#{nodefile}')
    puts "Return is: #{output}"
    if file_or_symlink_exists?('#{nodefile}') == true
      puts "Nodejs symlink exists."
    else
      puts "Nodejs symlink does not exist. Making the link now"
      sh "/bin/bash -c 'source ~/.nvm/nvm.sh && ln -sf $(which node) $(which node)js'"
    end
  end

  desc "Install nvm - Node Version Manager"
  task :install_nvm do
    begin
      if `which curl`.size.>(0)
        sh "curl https://raw.github.com/creationix/nvm/master/install.sh | sh"
      else
        sh "wget -qO- https://raw.github.com/creationix/nvm/master/install.sh | sh"
      end
      puts "NVM : https://github.com/creationix/nvm"
      puts "has been installed for your account. NVM is the node/npm version manager."
      puts "If you like RVM, you will feel like at home with NVM."
      puts
    rescue Exception => e
      puts e
      puts e.backtrace
    end
  end

  desc "Install a node version NODE_VERSION (default 4.4.3)"
  task :install_node do
    Rake::Task['nvm:install_nvm'].invoke unless ENV['NVM_DIR']
    node_version = ENV['NODE_VERSION'] || '4.4.3'
    sh "/bin/bash -c 'source ~/.nvm/nvm.sh && nvm install #{node_version}'"
  end
end