, when you apt-get installed mysql-server, it probably prompted you for the new mysql root password and you probably used the same one that you were using from befo... , log in to mysql using the root password you set above:
<code>mysql -p -u root # use your new pass
inzelnen Datenbank aus einer Dump-Datei ("–all-databases dump") die mehrere Datenbanken beinhaltet
<code>
mysql -u root -p --one-database dbname < backup.sql
</code>