Drush is a command line utility for administering Drupal websites, what you can do in the backend GUI you can do three times as fast on the command line. Version 5 of Drush can administer Drupal versions 6, 7 and 8. The only prerequiste that you need for this is command line access to your server. Learning Drush is quite easy, this tutorial covers the install and basic commands.
Getting Drush Installed on a cPanel/WHM Server
cd
wget http://ftp.drupal.org/files/projects/drush-7.x-5.8.tar.gz
curl -O http://ftp.drupal.org/files/projects/drush-7.x-5.8.tar.gz
tar -zxvf drush-7.x-5.8.tar.gz
rm drush-7.x-5.8.tar.gz
chmod u+x drush/drush
alias drush='~/drush/drush'
PATH=$PATH:$HOME/bin:/root/drush
source ~/.bash_profile
# drush core-status
cd home/public_html/
drush up
drush up modulename modulename
drush up drupal
drush cache-clear
The drush utility is very comprehensive to learn more check out the drush page.
BackUp and Restore
One command backups and restores - complete with files and database....could you ask for anymore?
drush archive-dump drush archive-restore
For the restore you need to point directly to the archive and declare the current site and confirm the overwrite - like so (approximate path, depending on your host):
drush archive-restore /path-to-archive/archive-dump/date.20121010112546/site.date20121010_112546.tar.gz --destination=/home/pathtodomain/public_html/ --overwrite
It is good practice to always take a backup before an upgrade in particular an upgrade to core Drupal, do the archive-dump, do the upgrade and if it breaks you can restore very easily and when upgrading Drupal via Drush make sure you do it when you are in the document root of your Drupal install.
Upgrading drush
To upgrade drush when new versions are released on a cPanel server it still has to be done via the command line using the command as below:
drush dl drush --destination=/path/to-the-drush-install-folder/
Using drush as root
If you use drush as the root user on a domain in a multi domain VPS type server and update Drupal/modules - this will remove the regular user/group names of the domain and assign unknown owner/groups in random number strings which will cause major errors.
You will need to reissue the user + group names to the file and folders of the domains including the .htaccess files
chown -R user:group * chown -R user:group .htaccess