Binary package “ruby-directory-watcher” in ubuntu oracular

Watch directory/files and Generate events by file change

 The directory watcher operates by scanning a directory at some interval
 and generating a list of files based on a user supplied glob
 pattern. As the file list changes from one interval to the next, events
 are generated and dispatched to registered observers.
 .
 Three types of events are supported: added, modified, and removed.