Still in the unixstuff directory, type
ls -a
As you can see, in the unixstuff directory (and in all other directories), there are two special directories called (.) and (..)
In UNIX, (.) means the current directory, so typing
cd .
means stay where you are (the unixstuff directory).
Notice that there is a space between cd and the dot.
This may not seem very useful at first, but using (.) as the name of the current directory will save a lot of typing, as we shall see later in the tutorial.
(..) means the parent of the current directory, so typing
cd ..
will take you one directory up the hierarchy (back to your home directory). Try it now.
Note: typing cd with no argument always returns you to your home directory. This is very useful if you are lost in the file system.