How to execute commands within Rake tasks?

Question

I have the rake tasks in my rails application. i want to run a commandline commands with in rake task. how can i do this. i tried by the following but fails

desc "Sending the newsletter to all the users"
task :sending_mail do
  run "cd #{RAILS_ROOT} && ar_sendmail -o -t NewsLetters -v"
  system "cd #{RAILS_ROOT} && ar_sendmail -o -t NewsLetters -v &"
end

The above run command throws run method undefined & System command not throwing any errors but not executed.

Answer 1

This links may help you run command line command into ruby ...

http://zhangxh.net/programming/ruby/6-ways-to-run-shell-commands-in-ruby/

Calling shell commands from Ruby

http://blog.jayfields.com/2006/06/ruby-kernel-system-exec-and-x.html

%x[command].each do |f|
  value = f
end