How to install Drush on Ubuntu
Drush is a great tool to administer the Drupal CMS. However there are a lot of ways to get it installed. Here is the easiest way I have found to install it for every user on an Ubuntu system.
For Ubuntu 10.04 LTS first enable backports. If you do not it will currently install version 2.) of Drush. Version 2 does not have the drush update command used below to update to the most recent version. With backports enabled it will currently install version 4.4 of Drush.
You can unable the backports after installing drush.
sudo apt-get install drush
drush –version should currently give you => drush version 4.4
Now update to the current version with:
sudo drush dl drush –destination=’/usr/share’
Then do:
sudo drush –version
The sudo is to allow it to install a package currently – http://download.pear.php.net/package/Console_Table-1.1.3.tgz if you do not include the sudo at the beginning you will get a message telling you how to install it manually. It is much easier to just let it install the package itself. If you want more info on the commands to manually install the console_table package see this webpage.
Info from: Installing/Upgrading Drush on Ubuntu
http://drupal.org/node/1248790