split_mysql_db_export.php

<?php

$fh_read = fopen('alldb.sql', 'r');

$fh_write = null;
$dbname   = null;
while ($line = fgets($fh_read)) {
    if (preg_match('@-- Current Database: `([^`]+)`@', $line, $m)) {
        if ($fh_write) {
            echo 'Closing ', $dbname, '<br>';
            fclose($fh_write);
        }
        $dbname   = $m[1];
        $fh_write = fopen($m[1] . '.sql', 'w');
        echo 'Opening ', $dbname, '<br>';
    }

    if ($fh_write) {
        fwrite($fh_write, $line);
    }
}

if ($fh_write) {
    fclose($fh_write);
}