linux-basic基本操作指令（最常用的）

-----
/         root directory
~         usr directory
./        current directory path
..        back
!cmd      invoke last cmd
&         run job in backround
----------
man        help
ls         list the dirctory
ls -a      list all  include hidden directory and file
ls -l      formal list 
ll         ls -l

cd             change directory 

pwd            present working directory

mkdir dir      creat a directory
touch          creat a file
vi file        vi  editor
gvim file      gvim editor
chmod 777 file  

cat file       look at the file context on terminal
more file      view the file
less file    view the file like gvim or vi

cp file1  file2   copy file1 to file2
cp -r dir1 dir2       copy dir1 to dir2