Drush or the Drupal Shell is one of the most powerful tools to use when you are working with Drupal. DreamHost provides php5 but uses php4 as the default for the php command line and in that case drush wont work, so here is a 3 step guide to setup drush on your dreamhost account.
For Using Drush Command Line tool you will need to enable SSH on your DreamHost Account.
Connecting via SSH
$ ssh [email protected]
$ vi .bash_profile
path to ,bash_profile would be /home/username/.bash_profile
Happy Drush :)