How to define two variable x=20, y=5 and then to print division of x and y (i.e. x/y) - bash

Question

I am using Ubuntu 14.04 and i tried this :

$ x=20  
$ y=5  
$ expr x / y 

But i got this error:

expr: non-integer argument

Answer 1

您必须展开变量以获取其值： $x和$y ：

expr $x / $y

Answer 2

Using modern Bash arithmetics:

echo $((x / y))

To assign the result to a variable z :

((z = x / y))

To verify the value of z :

echo $z