Task

Replace every occurring instance of a piece of text in a group of text files with another one.



For this task we want to replace the text   "Goodbye London!"   with   "Hello New York!"   for a list of files.




(for File '(a.txt b.txt c.txt)
   (call 'mv File (tmp File))
   (out File
      (in (tmp File)
         (while (echo "Goodbye London!")
            (prin "Hello New York!") ) ) ) )