```ruby
require 'rbconfig'

namespace :job do
  ruby_exec = File.join(RbConfig::CONFIG['bindir'], RbConfig::CONFIG['ruby_install_name'])
  job_controller = "#{Rails.root}/script/daemons/job_task_processor_ctl.rb"

  desc 'Retart the job task processor'
  task :restart => :environment do
    system(ruby_exec, job_controller, 'restart')
  end

  desc 'Start the job task processor'
  task :start => :environment do
    system(ruby_exec, job_controller, 'start')
  end

  desc 'Stop the job task processor'
  task :stop => :environment do
    system(ruby_exec, job_controller, 'stop')
  end
end
```

Use Rails.root.join instead of string concatenation.
user
```ruby
require 'rbconfig'

namespace :job do
  ruby_exec = File.join(RbConfig::CONFIG['bindir'], RbConfig::CONFIG['ruby_install_name'])
  job_controller = Rails.root.join('script', 'daemons', 'job_task_processor_ctl.rb').to_s

  desc 'Retart the job task processor'
  task :restart => :environment do
    system(ruby_exec, job_controller, 'restart')
  end

  desc 'Start the job task processor'
  task :start => :environment do
    system(ruby_exec, job_controller, 'start')
  end

  desc 'Stop the job task processor'
  task :stop => :environment do
    system(ruby_exec, job_controller, 'stop')
  end
end
```
assistant