Rake is a utility similar to make in Unix. You can say Rake is the make of ruby – the R uby m AKE. Rails defines a number of tasks to help you. http://www.tutorialspoint.com/ruby-on-rails/rails-and-rake.htm
Rake is Ruby Make, a standalone Ruby utility that replaces the Unix utility ‘make’, and uses a ‘Rakefile’ and .rake files to build up a list of tasks. In Rails, Rake is used for common administration tasks, especially sophisticated ones that build off of each other. ( rake tasks are defined in Rails.)
You can get a list of Rake tasks available to you, which will often depend on your current directory, by typing rake --tasks. Each task has a description, and should help you find the thing you need.