pfSense

/*

 * add_text_to_file($file, $text): adds $text to $file.

 * replaces the text if it already exists.

 */

function add_text_to_file($file, $text, $replace = false) {

	if (file_exists($file) and is_writable($file)) {

		$filecontents = file($file);

		$filecontents = array_map('rtrim', $filecontents);

		array_push($filecontents, $text);

		if ($replace) {

			$filecontents = array_unique($filecontents);

		}

		$file_text = implode("\n", $filecontents);

		@file_put_contents($file, $file_text);

		return true;

	}

	return false;

}