where can I find the rake tasks delivered with rails

I am looking for tasks like tmp:clear or db:migrate. Where can I find the code for these tasks. I remember seeing them before but don't recollect where.

Also, is there a way I can set some global variables in a .rake file that can be accessed by al开发者_JAVA技巧l tasks in that file without passing them as arguments to each task.

thanks, ash

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Figure out where you installed Rails.

$ gem environment

Look for the INSTALLATION_DIRECTORY.

$ cd [INSTALLATION_DIRECTORY]/gems/rails-[VERSION]/lib/tasks

Look for the .rake files in the tasks directory.

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You can check this as a starting point.