Using the diff-lcs gem

diff.rb

# an example of using the diff-lcs gem
# a mirror of the gem is hosted at http://github.com/defunkt/diff-lcs
# or `gem install diff-lcs`

require 'diff/lcs'

first, second = "hello, world!", "Hello, world!"
diff = Diff::LCS.diff(first, second)
patched = Diff::LCS.patch!(first, diff)

puts("Does the patched string equal the expected string?")
puts(second == patched)