+**Smart shell**\r
+\r
+- Put anything to terminal, the app will try to eval and display result as a python interactive shell.\r
+\r
+ + ``142857*2`` or ``101**3`` like a calculator.\r
+ + Even ``cal`` will show the calendar for current month.\r
+ + Put ``order_rainbow('anything')`` or ``random_rainbow('wahahaha')`` will make more fun :)\r
+\r
+**Screening Commands**\r
+\r
+- ``h`` will show the help.\r
+\r
+- ``c`` will clear the screen.\r
+\r
+- ``q`` will quit.\r