Weapon: environment variable $RANDOM

Reprinted from: http://blog.163.com/qingfeng_0105@126/blog/static/75062738201101711244243/Thanks
to the blogger for sharing!

The shell environment variable RANDOM, the value range is 0–32767

If we want to generate numbers in the range 0-25, we can use this environment variable to modulo 26: $ (($RANDOM%26))

exist$(()) 内部是可以省略取值的$Symbolic: $ (( $ RANDOM%26)) == $((RANDOM%26))

[root@localhost ~]# echo $(($RANDOM%26))
19
[root@localhost ~]# echo $((RANDOM%26))
22

practical application

If you want to get numbers in the range 1–68: $ (($RANDOM%68+1 ))

[root@localhost ~]# echo $(($RANDOM%68+1))
67

If you want to get numbers in the range 6–87: $ (($RANDOM%82+6 ))

[root@localhost ~]# echo $((RANDOM%80+6))
8