<?php

  $test = <<<EOD


This is some text
This is more text

That was an empty line


There were a couple more

    This is a line with whitespace at the beginning


Here are some empties at the end


EOD;

  echo "'".preg_replace('/^[\r\n]+|[\r\n]+$/m', '', $test)."'";

'This is some text
This is more text
That was an empty line
There were a couple more
    This is a line with whitespace at the beginning
Here are some empties at the end'