Не удается запустить Rails 4.1.7 сервер

Question

я сделал следующие команды:

1. рельсы новый [APP_NAME] [Исх. Demo]

2. кд демо [я вошел в каталог]

3. Rails -s (0r) рельсы -server

Когда я запускаю эту команду я получаю следующие ошибки.

/home/burhani/.rvm/gems/ruby-2.1.4/gems/execjs-2.2.2/lib/execjs/runtimes.rb:51:in `autodetect': Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes. (ExecJS::RuntimeUnavailable) 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/execjs-2.2.2/lib/execjs.rb:5:in `<module:ExecJS>' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/execjs-2.2.2/lib/execjs.rb:4:in `<top (required)>' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/uglifier-2.5.3/lib/uglifier.rb:3:in `require' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/uglifier-2.5.3/lib/uglifier.rb:3:in `<top (required)>' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/bundler-1.7.4/lib/bundler/runtime.rb:76:in `require' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/bundler-1.7.4/lib/bundler/runtime.rb:76:in `block (2 levels) in require' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/bundler-1.7.4/lib/bundler/runtime.rb:72:in `each' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/bundler-1.7.4/lib/bundler/runtime.rb:72:in `block in require' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/bundler-1.7.4/lib/bundler/runtime.rb:61:in `each' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/bundler-1.7.4/lib/bundler/runtime.rb:61:in `require' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/bundler-1.7.4/lib/bundler.rb:133:in `require' 
from /home/burhani/demo/config/application.rb:7:in `<top (required)>' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/railties-4.1.7/lib/rails/commands/commands_tasks.rb:79:in `require' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/railties-4.1.7/lib/rails/commands/commands_tasks.rb:79:in `block in server' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/railties-4.1.7/lib/rails/commands/commands_tasks.rb:76:in `tap' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/railties-4.1.7/lib/rails/commands/commands_tasks.rb:76:in `server' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/railties-4.1.7/lib/rails/commands/commands_tasks.rb:40:in `run_command!' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/railties-4.1.7/lib/rails/commands.rb:17:in `<top (required)>' 
from /home/burhani/demo/bin/rails:8:in `require' 
from /home/burhani/demo/bin/rails:8:in `<top (required)>' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/spring-1.1.3/lib/spring/client/rails.rb:27:in `load' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/spring-1.1.3/lib/spring/client/rails.rb:27:in `call' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/spring-1.1.3/lib/spring/client/command.rb:7:in `call' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/spring-1.1.3/lib/spring/client.rb:26:in `run' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/spring-1.1.3/bin/spring:48:in `<top (required)>' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/spring-1.1.3/lib/spring/binstub.rb:11:in `load' 
from /home/burhani/.rvm/gems/ruby-2.1.4/gems/spring-1.1.3/lib/spring/binstub.rb:11:in `<top (required)>' 
from /home/burhani/demo/bin/spring:16:in `require' 
from /home/burhani/demo/bin/spring:16:in `<top (required)>' 
from bin/rails:3:in `load' 
from bin/rails:3:in `<main>' 

Что я хочу делать.

Заранее спасибо.

Answer 1

Ваша ошибка Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes. (ExecJS::RuntimeUnavailable) означает, что у вас нет установленной версии Javascript. Установите Node.js (это полезно и для других целей). В Ubuntu:

$ curl -sL https://deb.nodesource.com/setup | sudo bash - 
$ sudo apt-get install -y nodejs 

Также вы должны установить утилиты сборки:

$ apt-get install -y build-essential 

Тогда вы будете иметь возможность запускать rails server команду.