Structure of system files and folders

The system is stored in the directory /bitrix/. This directory contains the following files and subdirectories.

/admin/ - administrative scripts;
/cache/ - cache files;
/help/ - help section;
/images/ - images used by the system and modules;
/modules/ - system modules. Each subdirectory of this directory has its own strict structure;
/php_interface/ - system service directory containing the following subdirectories and files:
- /include/ - subdirectory containing module helper user-editable scripts:
  - /catalog_export/ - the Commercial catalog module export scripts;
  - /statistic/ - CSV file handlers containing events for loading in the Statistics module;
  - add_top_panel.php - included when displaying the control toolbar; allows adding buttons to the toolbar.
- dbconn.php - database connection parameters;
- init.php - portal-wide additional parameters;
- after_connect.php - included right after the database connection is established;
- dbconn_error.php - included when a database connection error occurs;
- dbquery_error.php - included when a SQL query execution error occurs;
- /site ID/init.php - additional parameters for the site; the file is included right after a special constant SITE_ID is defined.
/templates/ - directory containing site templates and components; contains the following subdirectories:
- /.default/ - subdirectory with common files used by default templates; has the structure similar to the site template directory described below;
- /site template ID/ - subdirectory with site template; contains the following subdirectories and files:
  - /module ID/ - directory containing components of a specific module;
  - /lang/ - language files used by this template and components;
  - /images/ - directory containing images used by this template;
  - /page_templates/ - directory containing page templates and their description (stored in file .content.php);
  - header.php - prologue of this template;
  - footer.php - epilogue of this template;
  - styles.css - CSS used by this template;
  - .menu type.menu_template.php - template used to display a menu of the corresponding type;
  - chain_template.php - default template used to display the navigation chain.
/tools/ - here the installation procedure copies additional files that may be used with any pages of the site: help, calendar, image slideshow etc.;
/updates/ - this directory is automatically created by the update system;
header.php - a standard file which in its turn includes the current site template prologue; this file must be used with all pages of the public section;
footer.php - a standard file including the current site template epilogue; this file must be used with all pages of the public section;
license_key.php - this file contains the license key;
spread.php - this file is used by the Kernel module to spread user cookies among additional site domains;
redirect.php - used by the Statistics module to register link redirect events;
bx.php - default file used by the Advertising module to register banner click events;
stop_redirect.php - used by the Statistics module to display a message to a visitor currently in the stop-list;
activity_limit.php - used by the Statistics module to emit a message to the robot if it exceeds the activity quota;
rss.php - used by the Information blocks module to export the RSS content.

Note
Depending on the used edition, some directories and files may be unavailable.