As I am a curious sort, I always want to know exactly what is on my hard drive. One thing that always irks me about OS X is all of the hidden files and folders. Because of this, I prefer to keep them hidden. However, it is always good to know how to reveal them, and as such I will tell you how here.
Open Terminal and type the command:
defaults write com.apple.finder AppleShowAllFiles TRUE
This reveals the hidden files and folders.
Hit enter and then type the command:
This restarts Finder so the folders and files will be visible.
To revert it, the process is basically the same. Open Terminal and type:
defaults write com.apple.finder ShowAllFiles FALSE
Hit enter and then type:
A utilitarian trick all should know.