recursive.php

<?php

// 再帰的に置換をする

$baseDir = './hoge';

foreach (glob($baseDir . '/*/*.txt') as $fileName) {
    copy($fileName, $fileName . '.tmp');
    $string = file_get_contents($fileName . '.tmp');
    $pattern = '/ip4:/';
    $replacement = 'ip4\\\072';
    $string = preg_replace($pattern, $replacement, $string);
    file_put_contents($fileName . '.tmp', $string);
    rename($fileName . '.tmp', $fileName);
}