.htaccess

A .htaccess (hypertext access) file is a directory-level configuration file supported by several web servers, used for configuration of website-access settings such as URL redirection, access control, and MIME type handling. The leading dot makes it a hidden file in Unix-like environments. A site may contain more than one .htaccess file. The files are placed inside the web tree—inside directories and their subdirectories—which is why they are also called distributed configuration files. Each .htaccess file acts as a local override of the server's main configuration file (such as httpd.conf) for the directory it occupies and all subdirectories beneath it. The original purpose—reflected in the name—was per-directory access control, for example requiring a password to reach web content. In practice .htaccess files are now used to configure many other settings: content types, character encoding, CGI handlers, and URL rewriting rules. The .htaccess file format originated with the NCSA HTTPd server, where it was introduced to let shared-hosting users control access to their own directories without modifying the server-wide configuration. When the Apache HTTP Server project was founded in 1995 as a continuation of NCSA HTTPd, it retained the format and filename for compatibility. Other web servers, including Oracle iPlanet Web Server and the Zeus Web Server, later added .htaccess support even though their native configuration formats differ substantially. .htaccess files use a subset of the Apache HTTP Server directive syntax, which is the same format as the server's main httpd.conf configuration file.