Greetings,
During the installation I used Ubuntu MySQL Security Tweak from this documentation [URL SNIPPED]
You should be using: http://wiki.koha-community.org/wiki/Koha_on_ubuntu_-_packages It too has the same section: http://wiki.koha-community.org/wiki/Koha_on_ubuntu_-_packages#Ubuntu_MySQL_S... The tarball method of installation requires a level of system administration that many first time users do not have. Packages are much easier by comparison.
But now I need to connect Koha database with a Mysql -u root -p command.
$ mysql -u root -p [ I generally put the command on a different line, so it prompts you for the password. Otherwise, it may think 'command' is your password.] If you have forgotten your root password, Tomas has already pointed out how to do that. GPML, Mark Tompsett