Linux common commands

1. cd :"change directory"

2. the key of "tab" is automatic command line completion.

3. pwd : print the current working directory

4. the development environment of C/C++ under Ubuntu

         因为缺少一些必须的头文件，所以需要安装build-essential这个软件包

         run command: sudo apt-get install build-essential

         reference links: 

   http://blog.sina.com.cn/s/blog_49b531af0102e0be.html

http://blog.youkuaiyun.com/zwjsatan/article/details/8039277