3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $str = "127.0.0.1 domain.com #this is a comment"; preg_match('/^(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})[ \t]+([^ #]+).+#/',$str,$arr); print_R($arr);
Output for 4.3.0 - 7.3.0alpha1
Array ( [0] => 127.0.0.1 domain.com # [1] => 127.0.0.1 [2] => domain.com )