Sure, with search and replace you can do this. Note at the time it hits Search and replace you need to write html.
Should be something like this search:
Code:
(?P<bdy><body[^>]*>)
Replace should be something like this:
Code:
\g<bdy>\n<p>line1</p>\n<p>line2</p>\n<p>line3</p>\n<p>line4</p>\n<p>line5</p>\n