$re = '/(?m:^ => \d+:\s*<% binding.pry %>.*)/';
$str = ' 64: <div class="form-group">
=> 65: <% binding.pry %> # This one should match
66: </div>
67: <% binding.pry %> # This one should not be matched';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
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