cheat sheets.

Piston (http://piston.rubyforge.org/usage.html) is a tool for keeping bits and
pieces of your Subversion repository in sync with a remote repository. Like
svn:externals, but better. How?

With Piston, you import a remote repository and check it into your local
repository. You can then go nuts modifying it or periodically sync it up with
its remote origin using piston update.

All of the examples use the vendor/rails directory. But piston works on any
directory that you would use svn:externals with (IE Other plugin directories).

Note that for some commands to work you must first commit the imported files
into your repository.

Install:
  gem install piston -y

Import:
  piston import http://dev.rubyonrails.org/svn/rails/trunk vendor/rails

Update:
  piston update vendor/rails

Lock (doesn't allow updates):
  piston lock vendor/rails

Unlock:
  piston unlock vendor/rails

Status:
  piston status vendor/rails