shell生成指定范围随即整数

#!/bin/bash

function rand(){
    min=$
    max=$(($-$min+))
    num=$(cat /dev/urandom | head -n  | cksum | awk -F ' ' '{print $1}')
    echo $(($num%$max+$min))
}

rnd=$(rand  )
echo $rnd

exit 

#!/bin/bash
function rand(){    min=$1    max=$(($2-$min+1))    num=$(cat /dev/urandom | head -n 10 | cksum | awk -F ' ' '{print $1}')    echo $(($num%$max+$min))}
rnd=$(rand 2 100)echo $rnd
exit 0