Using Ruby, the following string:
"Lorem ipsum dolor\r\n Sit amet, consectetur adipisicing elit, sed do eiusmod
tempor incididunt ut labore et dolore magna aliqua.\r\n Ut enim ad minim
veniam, quis nostrud exercitation ullamco\r\n laboris nisi."
to the following:
"<p>Lorem ipsum dolor</p><p>Sit amet, consectetur adipisicing elit, sed do eiusmod
tempor incididunt ut labore et dolore magna aliqua.</p><p>Ut enim ad minim veniam,
quis nostrud exercitation ullamco</p> laboris nisi."
Don’t reinvent the wheel, there is a dedicated helper for this: simple_format.
See: http://api.rubyonrails.org/classes/ActionView/Helpers/TextHelper.html#method-i-simple_format