$re = '/\b([-\'])\b|(?!\n)[\W_]/m';
$str = 'That\'s
a-
tasty
tic-tac.
Or
-not?';
$subst = "\1";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php