Problem Statement

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.

Let's start with the solution:

files: select list "." 'f -> suffix? ".txtfile"

loop files 'file ->
    write file replace read file "Goodbye London!" "Hello New York!"