```ruby
require 'time'

module SrtShifter
	class Subtitle
		
		def initialize(options)
			@opts = options
		end

		def shift

			output_file = File.open(@opts[:output], 'w')

			lines = IO.readlines(@opts[:input])

			lines.each do |line|

				time_match = line.scan(/(\d{2}:\d{2}:\d{2},\d{3}) --\> (\d{2}:\d{2}:\d{2},\d{3})/)

				if $1.nil? && $2.nil?
					output_file.write(line)
				else
					new_start_time = convert_time $1 
      				new_end_time = convert_time $2 
      				new_line = "#{new_start_time} --> #{new_end_time}\n"

      				output_file.write(new_line)
				end
			end

			puts "Success!"
		end

		def convert_time time

			if @opts[:operation] == "SUB"
				@opts[:time] = -@opts[:time]
			end

			current_time = Time.parse(time)
			new_time = Time.at(current_time.to_f + @opts[:time])
			"#{new_time.strftime('%H:%M:%S')},#{new_time.usec/1000}"
		end
	end
end```

Change success message. Add 'elapsed time' stdout
user
```ruby
require 'time'

module SrtShifter
	class Subtitle
		
		def initialize(options)
			@opts = options
		end

		def shift

			start_time = Time.now

			output_file = File.open(@opts[:output], 'w')

			lines = IO.readlines(@opts[:input])

			lines.each do |line|

				time_match = line.scan(/(\d{2}:\d{2}:\d{2},\d{3}) --\> (\d{2}:\d{2}:\d{2},\d{3})/)

				if $1.nil? && $2.nil?
					output_file.write(line)
				else
					new_start_time = convert_time $1 
      				new_end_time = convert_time $2 
      				new_line = "#{new_start_time} --> #{new_end_time}\n"

      				output_file.write(new_line)
				end
			end

			end_time = Time.now

			puts "File created with success!"
			puts "Elapsed time: #{end_time-start_time} seconds."
		end

		def convert_time time

			if @opts[:operation] == "SUB"
				@opts[:time] = -@opts[:time]
			end

			current_time = Time.parse(time)
			new_time = Time.at(current_time.to_f + @opts[:time])
			"#{new_time.strftime('%H:%M:%S')},#{new_time.usec/1000}"
		end
	end
end```
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