directory listing
FAQ: How do I list the contents of a directory? How do I tell if a pathname is a file or directory?

Due to the fact that Common Lisp pathnames were designed to accommodate systems where the notion of files and directories may be radically different from the hierarchical Unix model (or might not even exist per se) this is implementation-dependent. Lucky for us CL-FAD exists to make this portable on Unix and Windows-like systems.