How do I install Bugzilla?

For Bugzilla you need...

• Per l(5.8.1 or above)
• MySQL
• Apache2
• Bugzilla
• Perl modules
• Bugzilla using apache

Some remarks up front:
If any of these are already installed just keep an eye on settings that need to be set. Check these with what you used and change them to your needs.
If you need information about Perl, MySQL, Apache these are some LAMP how to's: 1, 2, 3, 4, 5.
Note: also have a look at this how to (from Saariko in comment) in below does not work for you.
_{In case anyone finds typo's feel free to fix them or improvements feel free to add them in}
Here we go...

1. Perl
   Verify what perl you are using:
   

   perl -v
   

   It should show something like this:
   

   This is perl, v5.10.1 (*) built for i686-linux-gnu-thread-multi
   (with 53 registered patches, see perl -V for more detail)
   

   Natty uses 5.10. If yours is lower than 5.8.1 you need to upgrade it.
2. MySQL
   Verify if you have a MySQL running with
   

   mysql --version
   

   If not installed install mysql-server mysql-admin mysql-client
   Make sure to follow guidelines and set up a root account with a decent password. See the links above for how to set up a LAMP server if you need it. Create a user bugzilla (change it if you want something else)
   

   sudo useradd -d /home/bugzilla -m bugzilla
   sudo passwd bugzilla
   

   And create a database and set permissions for user bugzilla
   

   mysql -u root -p
   mysql> create database bugzilla;
   mysql> grant all privileges on bugzilla.* to bugzilla@localhost;
   

   You need database name, user name and password for the user later on.
3. Apache
   Verify if Apache is installed:
   

   apache2 -v
   

   and
   

   http://localhost
   

   should show a welcome page or a website. If not installed...install apache2 Configure apache2 as you normally would. See the links at the top for how to set up a LAMP server if you need more.
   And now for the important part... setting up bugzilla in apache2:
   

   sudo gedit /etc/apache2/apache2.conf
   

   and edit in the following ...
   

   Alias /bugzilla/ /var/www/bugzilla/
   
   Addhandler cgi-script .cgi .pl
   Options +Indexes +ExecCGI +FollowSymLinks
   DirectoryIndex index.cgi
   AllowOverride Limit
   
   

   (Note the trailing "/" on the first line)
   Add a user apache2 if you do not have this already.
   

    sudo useradd -d /home/apache2 -m apache2
    sudo passwd apache2
   

   Add the user to apache2 variables...
   

   sudo gedit /etc/apache2/envvars
   

   and include
   

    export APACHE_RUN_USER=apache2
    export APACHE_RUN_GROUP=apache2
   

   The cgi addhandler could be in another place if you instal bugzilla from the repositories (see apache cgi how to)
4. Bugzilla
   Install bugzilla3
   Or download the latest stable (4.0.2 at the moment) or latest cutting edge version from bugzilla. Short instruction on the latter:
   

    sudo tar -xvf bugzilla-4.0.2.tar
    sudo mv /download/bugzilla-4.0.2 /usr/local/
    sudo ln -s /usr/local/bugzilla-4.0.2 /var/www/bugzilla
   

   Make sure the directory had rw permissions:
   

    sudo chown -R www-data:www-data /var/www/bugzilla
   

5. Perl modules for Bugzilla
   Bugzilla uses a script checksetup.pl to check if everything is set up correcly and if things changed to set them up for you. By manually installing the perl modules you can skip this. Check if all modules are installed
   

    cd /var/www/bugzilla/
    sudo ./checksetup.pl --check-modules
   

   If not installed...
   

    sudo perl -MCPAN -e install
   

   localconfig holds the configurations and needs to be set up. So...
   

    sudo gedit localconfig
   

   and change $db_name to the database name, #db_user to the user and $db_password to the password you used during setup of MySQL.
   

    $db_name = 'bugzilla';
    $db_user = 'bugzilla';
    $db_pass = 'bugzilla@pwpspaswsword';
   

   After saving these settings
   

   cd /var/www/bugzilla/
   sudo ./checksetup.pl
   

   will add all kinds of tables to MySQL. Adding server group apache2 to bugzilla:
   

   sudo gedit /var/www/bugzilla/localconfig 
   

   and add
   

   $webservergroup = 'apache2';
   

   To include these changes do a
   

   cd /var/www/bugzilla/
   sudo ./checksetup.pl                       
   

   and this will ask you to setup your administrator for bugzilla.
6. It works!!
   Restart apache2
   

   sudo /etc/init.d/apache2 restart
   

   and open a browser and insert URL
   

   http://localhost/bugzilla/ 
   

   and I have a working bugzilla login page on my own machine.
   
   
   I think a much shorter answer would be much more helpful:
   

   sudo apt-get install bugzilla3