On Windows - since Vista onwards - I'm used to an extremely powerfully configurable instant file/folder/setting search feature: namely its instant indexed Start Menu search. Having a powerful computer, I add every single file and folder to the index so that any little file or folder I'm after (including both file name and extension), is immediately, instantly searchable right from the Start Menu.
It looks like Spotlight is OS X's equivalent of this.
Is there a way I can achieve the same thing, to index every single file on the hard drive, in OS X? So far I see no in-built way to add custom/system folders (or indeed all folders) on the Mac outside the ones it offers, like on this screenshot:
If there's no in-built solution such as a set of Terminal instructions, is there a good third party solution for this? (As always, free options are more desirable than paid.)