gistfile1.rb

DATA.each do |line|
 i = 0
 # For each match of "any character followed by the same character" do:
 marked = line.gsub(/(.)\1/) do |match|
   i += 1
   # return the match surrounded by asterisks from the block, which will
   # tell gsub to replace the match with that
   "*#{ match }*"
 end
 puts "{#{ i }} #{marked}"
end
__END__
test. AA. I greatXXrr love it.
audi tt uuuu yes.
stop here, axmmen.