With the following simple snippet of code you will be able to generate a list of all available two word combinations for a supplied list of keywords. It can be ran from the command line and can output a txt file of all matching domains.

domain-name-finder-usage.sh

// output will go to domains_found.txt in the same directory
php -f domain-name-finder.php

// output will go to the file specified as well as domains_found.txt in the same directory
php -f domain-name-finder.php > my-output-file.txt

domain-name-finder.php

<?php
/**
 * Simple function for checking the domain availability
 * of a .COM.
 *
 * @param string $whois         The whois host
 * @param string $domain        The domain to check
 */
function checkDomainAvailability($whois, $domain) {
        $s = fsockopen($whois, 43) or die("An error occurred attempting to connect to the whois server." . PHP_EOL);
        fwrite($s, $domain . PHP_EOL);
        $result = '';
        while(!feof($s)) $result .= fgets($s, 128);
        fclose($s);
        if (preg_match('/(No match|NOT FOUND)/i', $result)) return true;
        return false;
}

/**
 * A function to find all two word combinations from a user
 * specified list of words. This can be heavily modified
 * to try more variations of words in addition to trying
 * with hyphens.
 *
 * @param array $array  An array of words
 * @param array $output An array of two word combinations from the first parameter array
 */
function findCombinations($array, &$output) {
    if (!empty($array) && count($array) > 1) {
        $word = array_pop($array);
        foreach ($array as $val) {
                $output[] = $val . $word;
                $output[] = $word . $val;
        }
        findCombinations($array, $output);
    }
}

// an array of whois domains to randomly pick from to avoid the banhammer
$domains = array("whois.nsiregistry.net", "whois.crsnic.net", "whois.verisign-grs.com");

// an array of user chosen words to test for available combinations
$words = array('testing','site','tested','asdf','foobar');

// array combination of storage
$output = array();

// find all combinations
findCombinations($words, $output);

// a storage array of all available domains found from the $output array
$available = array();

$l = count($domains) - 1;

// check availability of all combinations
foreach ($output as $domain) {
        if (checkDomainAvailability($domains[rand(0, $l)], $domain.".com")) {
                echo $domain.".COM" . PHP_EOL;
                $available[] = $domain . ".COM";
        }
}

// store the matching domains in a file relative to this one
file_put_contents('./domains_found.txt', implode(PHP_EOL, $available));