$re = '/(?:> [^:]+: |\d+=|[ ,|<>])+/';
$str = '15:10:10,408 INFO <NioProcessor-11> Raw Message: 8=FIXT.1.1|9=317|35=D|49=verifix|';
$subst = "\n";
$result = preg_replace($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