OS X's command line and I have never been what I'd call 'friendly'; rather, we have a mutual respect and understanding about not messing with each other. (Well, as much of a mutual respect as one can have between a human being and a code window.) While the average person should never have any reason to visit Terminal, Apple's command line interface app actually does give you access to quite a few neat tricks and shortcuts. If you're willing to take a peek. What is Terminal?
Apple's Terminal app is a direct interface to OS X's bash shell — part of its UNIX underpinnings. When you open it, Terminal presents you with a white text screen, logged in with your OS X user account by default. Here's the important part: With a system administrator account and password, you have direct access to tweaking almost everything about your computer's software code; that means that while this little window provides great power, it comes with great responsibility. In short, be careful before using Terminal to execute commands, and make sure you understand what you're typing. You can also use Terminal to securely connect to other machines, web servers, and even create your own scripts, but those are how-tos for another day. For now, we're going to focus on using Terminal to explore your own computer.
Basic Terminal commands you should know Before we get started with the fun stuff, let's learn some basic Terminal terminology and commands. These form the framework for more complex interactions (aka, the fun stuff). How to execute a Terminal command You can type something in the Terminal window until you're blue in the face, but it won't execute until you press the Return key on your keyboard. At that point, it will either return an error if you've typed something incorrectly, or the command will execute. Unless you're executing a command that requires the display of text in Terminal, you won't have any indicator that what you've done has been successful; you'll just get a new line with your user name on it once the command is finished processing. When writing commands and paths in Terminal, almost everything is case sensitive: This means that you need to remember to properly capitalize 'Dock' when referring to the Dock, or OS X won't understand your command. What's a path?