Drush makes downloading multiple projects at once incredibly simple. You can download as many projects as you’d like in a single command, by simply separating each project name by a space.
drush dl [project_1 project_2]
drush dl admin_menu toolbar_admin_menu module_filter features devel views adaptivetheme corolla
The above command will download Admin Menu, Hide the Menu, Module Filter, Features, Devel, Views, the AdaptiveTheme base theme and the Corolla theme.
After we run that command, if we look at the directory structure, you’ll notice that the modules were downloaded into the “sites/all/modules” directory, and the themes were downloaded into the “sites/all/themes” directory. So, everything is placed where it is supposed to go. A common practice is to setup “contrib”, “custom” and “features” directories to keep your codebase organized. Drush is smart enough to place modules that you download from drupal.org into the “contrib” folder, if it exists.
I’ll delete these modules and themes, create those three directories and then re-download everything to show you how that works.
Now that the modules have been removed, I’ll create a new folder called “contrib” (which will contain all of the modules that are downloaded from drupal.org). I’ll also create one called “features” (which is where I would place the modules I’ve created with the Features module) and one called custom (which would contain any custom modules I’ve written for this site).
Now, I’ll re-run the last command (by pressing the up arrow on the keyboard) and watch Drush place the modules in the “sites/all/modules/contrib” folder. So, if you are using this directory structure (and I recommend that you do), Drush will utilize the “contrib” folder to keep your codebase clean.
As an aside, if you're wondering why it is recommended that you create these three folders, a great example is the Features module. You'll notice that the Features module's folder is simply "features". In order to keep the feature modules that we create with the Features module separate from the modules that we download from drupal.org, it's nice to have this directory structure so that you can update your feature modules and your contributed modules more easily.