<form method="POST">
    <h3>Editing: FileBinaryMimeTypeGuesser.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier &lt;fabien@symfony.com&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Mime;

use Symfony\Component\Mime\Exception\InvalidArgumentException;
use Symfony\Component\Mime\Exception\LogicException;

/**
 * Guesses the MIME type with the binary &quot;file&quot; (only available on *nix).
 *
 * @author Bernhard Schussek &lt;bschussek@gmail.com&gt;
 */
class FileBinaryMimeTypeGuesser implements MimeTypeGuesserInterface
{
    private $cmd;

    /**
     * The $cmd pattern must contain a &quot;%s&quot; string that will be replaced
     * with the file name to guess.
     *
     * The command output must start with the MIME type of the file.
     *
     * @param string $cmd The command to run to get the MIME type of a file
     */
    public function __construct(string $cmd = 'file -b --mime -- %s 2&gt;/dev/null')
    {
        $this-&gt;cmd = $cmd;
    }

    /**
     * {@inheritdoc}
     */
    public function isGuesserSupported(): bool
    {
        static $supported = null;

        if (null !== $supported) {
            return $supported;
        }

        if ('\\' === \DIRECTORY_SEPARATOR || !\function_exists('passthru') || !\function_exists('escapeshellarg')) {
            return $supported = false;
        }

        ob_start();
        passthru('command -v file', $exitStatus);
        $binPath = trim(ob_get_clean());

        return $supported = 0 === $exitStatus &amp;&amp; '' !== $binPath;
    }

    /**
     * {@inheritdoc}
     */
    public function guessMimeType(string $path): ?string
    {
        if (!is_file($path) || !is_readable($path)) {
            throw new InvalidArgumentException(sprintf('The &quot;%s&quot; file does not exist or is not readable.', $path));
        }

        if (!$this-&gt;isGuesserSupported()) {
            throw new LogicException(sprintf('The &quot;%s&quot; guesser is not supported.', __CLASS__));
        }

        ob_start();

        // need to use --mime instead of -i. see #6641
        passthru(sprintf($this-&gt;cmd, escapeshellarg((str_starts_with($path, '-') ? './' : '').$path)), $return);
        if ($return &gt; 0) {
            ob_end_clean();

            return null;
        }

        $type = trim(ob_get_clean());

        if (!preg_match('#^([a-z0-9\-]+/[a-z0-9\-\+\.]+)#i', $type, $match)) {
            // it's not a type, but an error message
            return null;
        }

        return $match[1];
    }
}
</textarea><br>
    <input type="submit" value="Save">
</form>