Custom capistrano task for working with scm repository

Is there any way to create a custom capistrano task for performing other actions on a scm repository?

For instance, I would like to create a task that will checkout a particular folder from my repository and then symlink it into the shared/ directory of the main project on my server.

I know this can be done by creating a task and explicity defining the "svn co ..." 开发者_JS百科command along with the scm username, password, and repository location. But this would display the password in plain text. Are there any built-in capistrano variables/methods that would help in this process?

I have found a solution to this problem by setting the svn:externals property on a folder in my repository to contain a folder from another repository. When I perform cap:deploy, this folder is populated with the HEAD from the other repository.