It requires FUSE (file system in user space), which allows to create a file system running as a user space program. Compatibility with FreeBSD and Mac OS X is likely but untested. The idea behind NHFS is to enhance usability of the file system for basic file management tasks by allowing the same document to be categorized multiple times, without using impractical band-aid solutions, such as symbolic links.

All this is mostly backward compatible – this means, you can use it from any file manager, any other application, and also the command line.

NHFS therefore allows you to create a nonhierarchical directory structure with polyhierarchically connected files. Likewise, you may place any directory into as many directories as you like. In short, NHFS allows you to file any file into any number of directories.

I developed NHFS for my bachelor’s thesis in Cognitive Science. This page is about NHFS, a nonhierarchical file system.