A .htaccess (hypertext access) file is a directory-level configuration file supported by several web servers, that allows for decentralized management of web server configuration. They are placed inside the web tree, and are able to override a subset of the server’s global configuration for the directory that they are in, and all sub-directories.

The original purpose of .htaccess—reflected in its name—was to allow per-directory access control by, for example, requiring a password to access the content. More commonly, however, the .htaccess files override many other configuration settings such as content type, character set, CGI handlers, etc.

.htaccess is a configuration file for use on web servers running the Apache Web Server software. When a .htaccess file is placed in a directory which is in turn ‘loaded via the Apache Web Server’, then the .htaccess file is detected and executed by the Apache Web Server software. These .htaccess files can be used to alter the configuration of the Apache Web Server software to enable/disable additional functionality and features that the Apache Web Server software has to offer. These facilities include basic redirect functionality, for instance if a 404 file not found error occurs, or for more advanced functions such as content password protection or image hot link prevention.

What is .htaccess?

.htaccess is a configuration file for use on web servers running the Apache Web Server software. When a .htaccess file is placed in a directory which is in turn ‘loaded via the Apache Web Server’, then the .htaccess file is detected and executed by the Apache Web Server software. These .htaccess files can be used to alter the configuration of the Apache Web Server software to enable/disable additional functionality and features that the Apache Web Server software has to offer. These facilities include basic redirect functionality, for instance if a 404 file not found error occurs, or for more advanced functions such as content password protection or image hot link prevention.

How to use .htaccess?

‘.htaccess’ is the filename in full, it is not a file extension. For instance, you would not create a file called, ‘file.htaccess’, it is simply called, ‘.htaccess’. This file will take effect when placed in any directory which is then in turn loaded via the Apache Web Server software. The file will take effect over the entire directory it is placed in and all files and subdirectories within the specified directory.

You can create a .htaccess file using any good text editor such as TextPad, UltraEdit, Microsoft WordPad and similar (you cannot use Microsoft NotePad).

An .htaccess file is a way to configure the details of your website without needed to alter the server config files. The period that starts the file name will keep the file hidden within the folder.

You can create the .htaccess file in a text editor (make sure to name it only .htaccess without any other extension or name) and then upload it to your site through an ftp client.

Additionally the placement of the .htaccess file is important. The configurations in that file will affect everything in its directory and the directories under it.

Things to be Aware of
Although an .htaccess page can be immensely useful and can be used to make marked improvement to a site, there are 2 things that it can influence.

One: Speed—the .htaccess page may slow down your server somewhat; for most servers this will probably be an imperceptible change. This is because of the location of the page: the .htaccess file affects the pages in its directory and all of the directories under it. Each time a page loads, the server scans its directory, and any above it until it reaches the highest directory or an .htaccess file. This process will occur as long as the AllowOverride allows the use of .htaccess files, whether or not the file the .htaccess files actually exists.

Two: Security—the .htaccess file is much more accessible than standard apache configuration and the changes are made live instantly (without the need to restart the server). Granting users permission to make alterations in the .htaccess file gives them a lot of control over the server itself. Any directive placed in the .htaccess file, has the same effect as it would in the apache configuration itself.

Generally speaking, Apache discourages the use of the .htaccess if the user can easily reach the apache configuration files themselves.

With that out of the way, let’s proceed with the .htaccess info.

Reference
www.wikipedia.com
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