Common terminal commands under Mac and vim common commands

Because very little command line, old despised, so today record a common command line:

CD Switch working directory
. Represents the current directory
.. Represents the top-level directory of the current directory
/root directory/directory separator
./Current Directory
.. /go to the top level directory
LS Displays the current directory so the file
mkdir Creating a new directory
RmDir Delete Empty directory, note is empty directory

Vim xx open xx file, if not created xx file, and pick to edit page
I just entered the editing page is not editable, so I can edit the input
ESC will exit edit mode by pressing ESC
: W Input: W is save just edit
: Q Exit Vim edit page
: Wq Save and exit

Common terminal commands under Mac and vim common commands