- substr: documentation ( source)
- var_dump: documentation ( source)
- strpos: documentation ( source)
- strtotime: documentation ( source)
<?php
$input = '[Tue Jun 18 22:25:32 BST 2013] NeoThermic likes B*witched - C"est La Vie';
$bracketpos = strpos($input, '[');
$endbracketpos = strpos($input, ']');
$datestamp = substr($input, $bracketpos + 1, $endbracketpos - $bracketpos);
$result = strtotime($datestamp);
var_dump($datestamp);
var_dump($result);