Task

Rename:

   a file called     input.txt     into     output.txt     and 
   a directory called     docs     into     mydocs.


This should be done twice:  
once "here", i.e. in the current working directory and once in the filesystem root.

It can be assumed that the user has the rights to do so.

(In unix-type systems, only the user root would have
sufficient permissions in the filesystem root.)




every dir := !["./","/"] do {
   rename(f := dir || "input.txt", dir || "output.txt")  |stop("failure for file rename ",f) 
   rename(f := dir || "docs", dir || "mydocs")           |stop("failure for directory rename ",f)
   }