: - If  old_p-  and  new_p-  resolve to the same existing file,
   no action is taken .
- Otherwise, the rename may include the following effects:
 - if new_p resolves to an existing non-directory file,
    new_p is removed; otherwise,
- if new_p resolves to an existing directory,
    new_p is removed if empty on POSIX compliant operating systems
    but may be an error on other operating systems.
 
A symbolic link is itself renamed, rather than the file it resolves to
. — 
end note