<!-- Collection of code snippets by Arne Vajhøj -->
<!-- posted to eksperten.dk, usenet and other places (2002-now) -->
<?php

function repl($s) {
	if(preg_match('/^\[\d+\].*$/', $s) || preg_match('/^\<\d+\>.*$/', $s)) {
		return $s;
	} else {
		return preg_replace('/(\d+)(.*)/', '[$1]$2', $s);
	}
}

echo repl('[23] OK') . "\r\n";
echo repl('<23> OK') . "\r\n";
echo repl('23 OK') . "\r\n";

?>