Not recommended to hard-code files within snake file

Can organize sample names, file paths, and software parameters in a YAML configuration file

YAML - serialization language that transforms data into a format that can be shared between systems

With snakemake, configuration file is a reference for the workflow

Yet another markup language- YAML Ain’t Markup Language  Easy to keep things organized within a single file While showing, good to have separate config files rather than one huge one and commenting sections out