Eric's thoughts

There are a few differnt options to execute shell cmd in ruby rake task:
1. exec
2. system
3. backtick “
4. %x{}

%x{} returns back to rake task whereas  exec and system does not (exec replace the current process with a new one, system return true or false )
so if you  do something like

desc 'example'
  task :example do
    exec {cmd_one}
    exec {cmd_two}  
  end
end

cmd two will never get executed. Switch to %x{} instead.

btw, you can run multiple rake task like this

desc 'example'
  task :example do
    Rake::Task['name_space:task_one']
    Rake::Task['name_space:task_two']
  end
end