《Red Hat Linux 用户基础》，这本书是红帽学院官方指定教程，但是没有附答案。这个就是那本书的答案(官方的，绝对权威)，希望能对学习linux的同学有帮助。- Red Hat Linux user base,　This book is the designated official Red Hat Academy curriculum, but not attached to the answer. This is the answer to that book (official, absolute authority), hoping to learn linux to help students.