+val tilde_expand: string -> string (** bash-like (head) tilde expansion *)
+val safe_remove: string -> unit (** removes a file if it exists *)
+val safe_rmdir: string -> unit (** removes a dir if it exists and is empty *)
+val is_dir_empty: string -> bool (** checks if the dir is empty *)
+val rmdir_descend: string -> unit (** rmdir -p *)
+
+
+ (** find all _files_ matching test under a filesystem root *)
+val find: ?test:(string -> bool) -> string -> string list