def node_module_exists(command, install_instructions = 'npm install -g')
      cmd = `if hash #{command} 2>/dev/null; then echo "true"; else echo "false"; fi`
      if cmd.include? "false"
        command_msg = "Missing command #{command}"
        abort "#{command_msg}: Please run `#{install_instructions} #{command}` And try again\n"
        exit 1
      end
    end
def node_module_exists(command, install_instructions = 'npm install -g')
      cmd = `if hash #{command} 2>/dev/null; then echo "true"; else echo "false"; fi`
      if cmd.include? "false"
        command_msg = "Missing command #{command}"
        abort "#{command_msg}: Please run `#{install_instructions} #{command}` And try again\n"
        exit 1
      end
    end
Verify that command is available on the box before continuing

 @param command [String] command to check
 @param install_instructions [String] how to install the missing command
 @return [void] aborts the action if command not found