虽然在逃避考试，但是感觉今天理清了自己的思路，变得开心了很多。
下面要学习的 pracitial unix 有下面的几个部分：
grep，regular expression，ZSH，vim&emacs，basic and advanced GDB features,permission, working with file systems, revision control, Unix utilies, environment customization, using python for shell scripts.
shell:the shell allows you to drive your computer in manual mode. The shell takes input from a user, interprets the input as commands, then directs the operation of a computer by executing the commands. Shells come in a few flavor such as bash, zsh, and many others but most likely your machine is running a bash shell. This is a very important concept so make sure those sentences sunk in. In order to interact with your shell, you open a graphical program called the Terminal. If you're running Ubuntu, you can find the Terminal application if you go to your Dash home then search for 'Terminal'. If you're using your Mac, you can also perform a search for the Terminal application. We'll be using the terminal quite often so I suggest you create a shortcut to it by dragging it to your dock or navigation bar once you've found the application. Once you've got your terminal up and running, you can enter and execute the commands you've seen in the intro videos.
在Linux中启动vim：vimtutor
在Linux中启动Emacs：emacs -nw
sudo（今天长知识了）：super user do
sudo apt-get install emacs24
Linux config file for vim is .vimrc
emacs is .emacs
ZSH is .zshrc
bash is .bashrc
明天就要考试了,还是加油喽,coding is life.