$re = '/(?:[ ]{4,}|\t{1,})(.+)/m';
$str = 'This is a code block:
I need capturing along with
this line
This is a code fence below (to be ignored):
``` json
This must have three backticks
flanking it
```
I love `inline code` too but don\'t capture
and one more short code block:
Capture me
';
preg_match_all($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