Contrary to list.files(), this method guarantees to work
 recursively.  Moreover, when subdirectories are processed recursively,
 directory names are also returned.
"listDirectory"(path=".", pattern=NULL, recursive=FALSE, allNames=FALSE, fullNames=FALSE, ...)character string of the filename pattern passed. See
   list.files() for more details.TRUE, also files starting with a period are returned.TRUE, the full path names are returned.vector of file names.
list.files() is used.