cfnet-fs is a program that, when executed on a Linux device (e.g. ModularPi), creates a virtual file system (i.e. a set of directories and files) corresponding to the set of CFNET IO modules connected to the device. Reading from and writing to those files effectively reads from and writes to the CFNET IO modules.
This makes it possible to automate the CFNET IO modules from any programming language (e.g. C/C++, C#, Python, Java, etc.) or tool (e.g. Codesys, NODE-Red, etc.) that can do file IO, even a text editor.