Get Random Number in Bash

system variable $RANDOM can be used to generate a random number between 0 and 32767, in case you want to get a random number between 0 and 10, you may do the following

$ declare -i number=$RANDOM*10/32767
$ echo $number

declare options/typeset:
-i integer: following variable will be an integer
-r readonly: following variable will be readonly, cannot be reset.
-a array: following variable will be an array.
-f function
-x export: following variable will be exported.

$ sum=100+50
$ echo $sum
$ 100+50
$ declare -i sum=100+50
$ echo $sum
$ 150

Notes:

• when declare variable, there should be no space before/after “=”
• what is bash?
• defauly variable type is string
• if you declare variable as readonly by mistake, you need to logout and login again to undo the mistake