url redirects

How to redirect visitors to another directory based on the URL given?

e.g. visitor goes to http://www.mysite.com/variable it should be redirected to http://www.mysite.com/subdirectory/variable

Many thanks in advance

>>14
This thread has half as many posts as the one about omgoptimizing assembly posted at roughly the same time. Your victim complex is unwarranted.

Considering your incorrect spelling of ``/prog/'', I'm guessing you're one of the Sepples faggots. The reasons those threads receive less attention isn't because they're ``about programming''.