What is .htaccess Files

.htaccess files (or “distributed configuration files”) provide a way to make
configuration changes on a per-directory basis. A file, containing one or more
configuration directives, is placed in a particular document directory, and the
directives apply to that directory, and all subdirectories thereof.

Directives

“Directives” is the terminology that Apache uses for the commands in Apache’s
configuration files. They are normally relatively short commands, typically
key value pairs, that modify Apache’s behavior. An .htaccess file allows
developers to execute a bunch of these directives without requiring access to
Apache’s core server configuration file, often named httpd.conf. This file,
httpd.conf, is typically referred to as the “global configuration file” and I will
refer to it with that name or its short filename equivalent.
This feature is ideal for many hosting companies deploying a shared hosting
environment. The hosting company will not allow its customers to access the
global configuration file, which ultimately affects all of the customers hosted on
that server. Instead, by enabling .htaccess, they give each of their customers
the power to specify and execute their own Apache directives in their own
directories and subdirectories. Of course it’s also useful to the single
developer, as you will see.
It’s worth mentioning that anything that can be done with a .htaccess file can
be done in the httpd.conf file. However, NOT everything that can be done in
httpd.conf can be done in a .htaccess file. In fact .htaccess files must be
enabled in the httpd.conf file in order to be executed at all. Once enabled,
their power can be limited to certain “contexts” so that they may be allowed
to override some settings but not others. This gives the system administrators
more control over what they let other developers get away with in their
.htaccess files.

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