I've got a file with wrong line separators - how do I convert?

Hi -

I'm using RubyMine on a mac, and I want unix line endings for all files. A few files in the project I'm using have (for some unknown reason) windows line endings, and I want these converted when I change any contents. Is there any way to make Ruby mine do this automatically? manually? At least indicate when the file's line separators don't match the project's?

thanks

Tim