what is .htaccess file?

hi friends..
i want to know about the .htaccess file... if you know completely please give some basic concepts and explain about it.. and what are the syntax were used in it... and explain about each syntax..

 

.htaccess (hypertext access) is the default name of a directory-level configuration file

Have a look at http://en.wikipedia.org/wiki/Htaccess

 

.htaccess, with this file, you can do anything with ur hosting.