What's the purpose of each directory?

Question

What's the purpose of the directories used from Drupal?

Answer 1

I haven't seen one, so let's start a list right here. In Drupal 5, 6 and 7 the structure looks like this:

• includes - include files with php functions and classes that make up the Drupal API
• misc - miscellaneous assets like javascript files and images
• modules - Drupal core modules (not meant for contrib and custom modules)
• profiles - installation profiles
• scripts - shell scripts for developers and administrators

• sites - all files that are added by a developer to create a site

  • sites/all/libraries - 3rd party libraries, eg. a wysiwyg editor
  • sites/all/modules - contributed and custom modules
  • sites/all/themes - contributed and custom (sub)themes
  • sites/default - contains the default settings.php
  • sites/default/files - the default directory for user-uploaded files
  • sites/example.com/modules - the site-specific modules directory in a multisite structure
  • sites/example.com/themes - the site-specific themes directory in a multisite structure
  • sites/example.com/files - the site-specific directory for user-uploaded files in a multisite structure
• themes - Drupal core themes

Answer 2

The accepted answer is good. This is just my two cents to expand other answers, as a site developer on Drupal 7. It is easier to navigate when upgrading many custom modules, few features, and parent/custom sub-themes.

• sites/all
  • /modules
    • /contrib
    • /custom
    • /features
  • /libraries
  • /themes
• sites/example.com
  • same as sites/all/* with site-instance specific needs when appropriate