rand-string.php

<?php
function swap(&$o, $a, $b) {
    $x = $o[$a];
    $o[$a] = $o[$b];
    $o[$b] = $x;
}

$letters = 'abcdefghijklmnopqrstuvwxyz';
$lettersUp = strtoupper($letters);
$digits = '0123456789';
$misc = '^+-()[]';

$alphabet = $letters . $lettersUp . $digits . $misc;
$len = strlen($alphabet);

$size = $argv[1] ?? 30;

for ($i = 0; $i < $size; $i++) {
    for ($j = 0; $j < $len; $j++) {
        $a = random_int(0, $len - 1);
        $b = random_int(0, $len - 1);
        swap($alphabet, $a, $b);
    }
}

for ($i = 0; $i < $size; $i++) {
    $k = random_int(0, $len - 1);
    echo $alphabet[$k];
}

echo PHP_EOL;

curl -fSsL \
"https://gist.github.com/alichry/ef8c049ced20d59c03b713\
498706fe6a/raw/c7203d6e66a146f4f5e8b3c6027014246\
85c1685/php-rand-string.sh" | php -- 22