3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php var_dump(preg_replace('#_([a-z])+\.(?:jpg|gif|png|jpeg)$#','_n$1','http://photos-h.ak.fbcdn.net/hphotos-ak-frc3/t1.0-0/1538683_705144079517314_1930601228_n.jpg'));
Output for 4.3.0 - 7.2.0
string(89) "http://photos-h.ak.fbcdn.net/hphotos-ak-frc3/t1.0-0/1538683_705144079517314_1930601228_nn"