Google Dorking is a famous way of hacking, and its incredibly simple. Theres a whole database of the code at
http://www.exploit-db.com/google-dorks/ which you can use. It's used to get passwords, find website vulnerabilities, insecure admin panels, etc.
Lets talk about the simple code, and find passwords:
filetypeThis is to find filetypes, such as "filetype:sql",(or for what the tutorial is, we use .txt) Which will display websites that have SQL files on the site, which you can use to find MySQL table information.
inurlThis is to see whats the title of a website. Such as "Passwords.txt" or something. So it looks like "inurl:passwords".
If you put these two together you would google this:
filetype:txt inurl:"Passwords".This is just an example and might not always have password files, but the more you learn you can find constant working ones such as
ext:sql intext:@gmail.com intext:passwordThat one will find gmail passwords, or credit card numbers or anything in between.
If you goto exploit-db.com/google-dorks you can find TONS of these, and the ones that aren't there can be Googled or searched on YouTube. Anything is possible, from hacking and moving security cameras across the world, to hacking PayPal accounts.
It's all in your hands babies