gistfile1.php

#!/usr/bin/env php
<?php
/**
 * `grep` is faster for single terms.
 *
 * `grep -i .php /path/to/access.log`
 *
 *   vs.
 *
 * `this-script /path/to/access.log .php`
 */

$script = array_shift($argv);
$file   = array_shift($argv);

if (!$file) {
        echo "Usage: {$script} <file> <retain...>\n\n";
        exit;
}
if (!is_file($file)) {
        echo "Error: {$file} does not exist\n\n";
        exit;
}

$retain = $argv;

if (empty($retain)) {
        echo "Error: nothing to retain. You must specify at least one string to retain.\n\n";
        exit;
}

$fp = fopen($file, 'r');

while ($line = fgets($fp)) {
        foreach ($retain as $search) {
                if (stripos($line, $search) !== false) {
                        echo $line;
                        continue 2;
                }
        }
}

?>