PHP 如何与 shell 命令互动？

$output = exec('ls -l');
echo $output;

$output = shell_exec('ls -l');
echo $output;

$handle = popen('ls -l', 'r');
while (($buffer = fgets($handle)) !== false) {
    echo $buffer;
}
fclose($handle);

$descriptorspec = array(
    0 => array("pipe", "r"),  // stdin is a pipe that the child will read from
    1 => array("pipe", "w"),  // stdout is a pipe that the child will write to
    2 => array("pipe", "w")   // stderr is a file to write to
);
$process = proc_open('ls -l', $descriptorspec, $pipes);

// 获取文件权限
$output = shell_exec('ls -l /var/www/html');

// 解析输出
$lines = explode("\n", $output);
array_shift($lines); // 移除标题行

foreach ($lines as $line) {
    $parts = explode(' ', $line);
    $permissions = $parts[0];

    // 提取权限信息
    $owner = substr($permissions, 1, 3);
    $group = substr($permissions, 4, 3);
    $other = substr($permissions, 7, 3);

    echo "Owner: $owner, Group: $group, Other: $other\n";
}