If the -a option is given, filenames beginning with dot (.) will be listed. Ordinarily, they are skipped.
If the -d option is given, directory contents will not be listed; the directories themselves will be.
If the -l option is given, a long format listing showing the file size, type, and link count will be displayed instead of just the filenames.
If the -R option is given, subdirectories encountered will be listed recursively.
If the -s option is given, the number of filesystem blocks used by each object will be displayed in addition to other information.
If no paths are specified, the current directory is assumed.