hidden folders in Internet

very often in Internet I see links like this:

www.abcde.com/~main/material/hello

and this part ~main/material/hello is grey, if I remove hello I receive acces开发者_C百科s forbidden, can somebody explain, what is this system, and is it possible receive access?

Directory listing is disallowed on www.abcde.com/~main/material/, but you have access to it's content.

They've configured the web server to only allow access to certain areas. You won't be able to receive access to it.

Depends on the web server. On Apache this can be done with

Options -Indexes

what do you mean it is grey? the link text on a page? That can be any colour that the page owner wants, but I don't remember seeing a grey link.

What happens if you type www.abcde.com/~main/material/hello directly into the browser's address window?

If you remove "hello" and receive access forbidden it is because there is no public access to www.abcde.com/~main/materia - give up, you will never access that without a password.

The tilde (~) is *nix convention for a user's home directory. Using it in the URL tells an appropriately-configured web server to look in a directory in the user's home directory for the files to show via the web server.