Ruby script to compare two text files - analysed what lines exist in file1 that do not in file2.

compare_lines.rb

#!/usr/bin/ruby

# script to compare and see what lines are in file1 but not file2

f1 = File.open('file1.txt')
f2 = File.open('file2.txt')

file1lines = f1.readlines
file2lines = f2.readlines

file1lines.each do |e|
  if(!file2lines.include?(e))
  puts e
  end
end

Hello...
How about if you want to compare two files if everything in file1.txt matches that in file2.txt?
And if file2.txt is shorter, it should copy the remaining lines from file1.txt into it