These projects are meant to get you warmed up with programming in the C++/UNIX environment. None are meant to be particularly hard, but should be enough so that you can get more comfortable programming.
Realize the best thing you can do to learn to program in any environment is to program a lot. These small projects are only the beginning of that journey; you'll have to do more on your own to truly become proficient.
Tip of the hat to Remzi and Andrea Arpaci-Dusseau for the amazing textbook and projects, which we borrow from heavily.