#Example row of data: 11/10/2010:Location: Home :Gender: M :Comment: I just wanted to say I had a great time at the party! :Email: [email protected]

file = File.new("data.dlm", "r")
	File.open('output.txt', 'w') do |f1| while (line = file.gets)
	sub_string = line.scan(/:Comment:([^<>]*):Email:/imu).flatten
	f1.puts sub_string
	end
end
file.close

This regular expression used in Ruby will extract the characters between single or multi-character delimiters.  It helps when you have strange delimiters such as \":delimeter1: text I want to grab goes here :delimiter2:\"

Strip characters from between two delimiters

regex, data, text

Ruby