Path module provides string operations for manipulating file paths. Fs module provides methods for actual file operations.
That way, you can take a path to a file from user, make some string operations on given path using path module, then do some file operations on a newly calculated path using fs module.
I'm writing plugins in some (I hope) meaningful way; os for accessing info on operating system, then path to make path operations, then fs to use those paths for making file operations.
Next, I'll try to implement URL and query string modules for URL� operations. That way we have some basic methods and modules exposed to use node.is part of node-webkit.