mkdir
We're currently in the Desktop folder. Lets make a new directory.
mkdir will make a new directory in our current location. mkdir also needs to know the name of the folder to create. mkdir <new_folder_name>
Lets make a folder called git_tutorial. This will be perfect if you're continuing into the next git book to learn Git.
(Make sure you don't have a folder already on your Desktop with that name)
$ mkdir git_tutotial

If we look inside git_tutorial, we'll see that its empty.
$ ls git_tutorial

Now, lets create a nested directory, and cd into it.
$ mkdir git_tutorial/nested
$ cd git_tutorial/nested
