Need to apply some manipulation to strings in arbitrary apps? Clipboard filtering to the rescue! (OS X 10.6+ only, but can be adapted to other versions and OSes.)

gistfile1.rb

require 'osx/cocoa'
pboard = OSX::NSPasteboard.generalPasteboard

x = nil
loop do
	new_x = `pbpaste`
	if new_x != x
		x = new_x
		y = x.gsub(/Art\./, 'art').gsub(/[^a-zA-Z0-9]/, '').downcase
		puts y
		pboard.clearContents
		pboard.writeObjects [y]
	end
end