user
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.
assistant
(formerly Perl 6)

Current Raku implementations do not yet support the -i flag for editing files in place, so we roll our own (rather unsafe) version:

```
slurp($_).subst('Goodbye London!', 'Hello New York!', :g) ==> spurt($_)
    for <a.txt b.txt c.txt>;

```