Ruby script to update file prefixes recursively. Useful to quickly change filenames to match a class prefix change in an Xcode project.

prefix_changer.rb

#!/usr/bin/env ruby
 
class String
  def starts_with?(prefix)
    prefix = prefix.to_s
    self[0, prefix.length] == prefix
  end
end
 
old = 'RJD' # old prefix
new = 'CPT' # new prefix
 
Dir[File.join("/path/to/project/files/**/#{old}")].entries.each do |path|
  basename = File.basename(path)
  dirname = File.dirname(path)
  if (basename.starts_with? old)
    new_basename = new + basename[old.length, basename.length - old.length]
    new_path = File.join(dirname, new_basename)
    File.rename(path, new_path)
    puts "#{basename} -> #{new_basename}"
  end
end