Shell script random number generating

Question

var=$RANDOM creates random numbers but how can i specify a range like between 0 and 12 for instance?

Answer 1

If you already have your random number, you can say

var=$RANDOM
var=$[ $var % 13 ]

to get numbers from 0..12.

Edit: If you want to produce numbers from $x to $y, you can easily modify this:

var=$[ $x + $var % ($y + 1 - $x) ]