05-16-2010
Generate random number
I saw this formula to generate random number between two specified values in shell script.the following.
$(((RANDOM%(max-min+divisibleBy))/divisibleBy*divisibleBy+min))
Give a example in book.
Generate random number between 6 and 30.like this.
$(((RANDOM%30/3+1)*3))
But I have a question , how to get a divisibleBy number is ok.
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RAND(3) 1 RAND(3)
rand - Generate a random integer
SYNOPSIS
int rand (void )
DESCRIPTION
int rand (int $min, int $max)
If called without the optional $min, $max arguments rand(3) returns a pseudo-random integer between 0 and getrandmax(3). If you want a
random number between 5 and 15 (inclusive), for example, use rand(5, 15).
Caution
This function does not generate cryptographically secure values, and should not be used for cryptographic purposes. If you need a
cryptographically secure value, consider using random_int(3), random_bytes(3), or openssl_random_pseudo_bytes(3) instead.
Note
On some platforms (such as Windows), getrandmax(3) is only 32767. If you require a range larger than 32767, specifying $min and
$max will allow you to create a range larger than this, or consider using mt_rand(3) instead.
PARAMETERS
o $min
- The lowest value to return (default: 0)
o $max
- The highest value to return (default: getrandmax(3))
RETURN VALUES
A pseudo random value between $min (or 0) and $max (or getrandmax(3), inclusive).
EXAMPLES
Example #1
rand(3) example
<?php
echo rand() . "
";
echo rand() . "
";
echo rand(5, 15);
?>
The above example will output something similar to:
7771
22264
11
SEE ALSO
srand(3), getrandmax(3), mt_rand(3), random_int(3), random_bytes(3), openssl_random_pseudo_bytes(3).
PHP Documentation Group RAND(3)