php_replace_short_tags.php

#!php-cli
<?php

$path = realpath('public');

$objects = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($path), RecursiveIteratorIterator::SELF_FIRST);
foreach($objects as $name => $object)
{
	$path_parts = pathinfo($name);
	if (! isset($path_parts['extension']) OR $path_parts['extension'] !== 'php')
	{
		continue;
	}

	$initial_file_contents = file_get_contents($name);
	$replaced_file_contents = preg_replace(
		array(
			"/<\?=([^\?]+)\?>/s",
			"/<\?[^p]/s"
		),
		array(
			"<?php echo $1; ?>",
			"<?php\n"
		),
		$initial_file_contents);

	if (strcmp($initial_file_contents, $replaced_file_contents) != 0)
	{
		file_put_contents($name, $replaced_file_contents);
		echo "Converted: {$name}\n";
	}
}

test.php

<?
$var = 'test';
echo $var;
?>

<?=$test?>

<?= $test ?>

<? $newVar = 'lol'; ?>