A simple random string generator in PHP

A random string generator is useful for all php projects. You may use it to create tokens or to create new random password.
The generateString function generates a new random string $length characters long.

The following script generates 20 random strings whose length is 1 t 20.

<?php
for ($x = 0; $x <= 21; $x++)
{
	echo generateString($x);
	echo "\n";
}
function generateString($length)
{
	echo $length."\t";
	if($length<=0 || $length>20)
	{
		$randomString = "------------------";
	}
	else
	{
		$randomString = substr(str_shuffle("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"), 0, $length);
	}
	return($randomString);
}
?>

Try running it

/var/www# php RandomStringGenerator.php
0 ------------------
1 9
2 f9
3 nTt
4 EieK
5 i2lQC
6 DH4dpt
7 IiGuD09
8 2fBJe3ML
9 m2XK6Q4n5
10 8emRLhJo6S
11 NbQoirYh3CM
12 0sHnvuUTCPAw
13 3vftQTzdaV5h6
14 xWzvlA0ZJnOtB4
15 n6F30hKeQdUNo1Y
16 kxzXHyMIPwAhRs6n
17 2hklu16esQU7gF0oR
18 vA7wp68tVT0l12niD5
19 KPyE0eFXIsnfUOZQo8N
20 yTGv6WMuqgoXiSeBKj2F
21 ------------------

Gg1