3v4l.org

run code in 300+ PHP versions simultaneously
<?php $text = 'The $girl$ is a $good$ person, and keep $$this$$.'; echo preg_replace('/\${2,}[^\s$]+\${2,}(*SKIP)(*FAIL)|\$[^\s$]+\$/', '\$$0\$', $text);

preferences:
114.34 ms | 1388 KiB | 5 Q