I installed MediaWiki on a server at work yesterday. The web install is pretty straight forward, even I could get it right.
One thing I learnt was how to reset the root password on an MySQL database when it is not known-
1. stop MySQL (init.d/mysql stop)
2. Restart mysqld with the –skip-grant-tables option (I just added that argument to the init.d script and removed it after).
3. Connect to the mysqld server:
# mysql -u root mysql
4. At the mysql prompt:
mysql> UPDATE user SET Password=PASSWORD(‘newpasswd’)
mysql> FLUSH PRIVILEGES;
5. Stop mysqld and restart it normally.
# mysql -u root -p