Drush is a command line shell and scripting interface for Drupal, a veritable Swiss Army knife designed to make life easier for those of us who spend some of our working hours hacking away at the command prompt.
Simple tasks like clear cache can take long time using the web interface. Using drus you just need to use the following command:
Ant It will display something like this:
Enter a number to choose which cache to clear.  : Cancel  : all  : drush  : theme-registry  : menu  : css-js  : block  : module-list  : theme-list  : registry  : token  : views
From this moment you can select if you want to clear the cache of something specific or All.
Other option very useful it to download modules for that you follow this command:
drush dl module_name
There are many other options for drush, you can find at the project page: