'nolinks' causes dd to fail if the file has multiple hard links,
on hosts that support this (e.g., Solaris 10 and later).
+ ls accepts the new option --group-directories-first, to make it
+ list directories before files.
+
rm now accepts the -I (--interactive=once) option. This new option
prompts once if rm is invoked recursively or if more than three
files are being deleted, which is less intrusive than -i prompting