Are there any best practices to follow when executing shell commands in PHP, especially when dealing with complex commands like in this case?

When executing shell commands in PHP, especially complex ones, it's important to properly sanitize user input to prevent command injection attacks. One way to do this is by using escapeshellarg() or escapeshellcmd() functions to escape any user input that will be passed to the shell command.

// Example of executing a shell command in PHP with proper input sanitization
$user_input = $_POST['user_input']; // Assuming this is user input that will be passed to the shell command

// Sanitize user input using escapeshellarg()
$sanitized_input = escapeshellarg($user_input);

// Execute the shell command with the sanitized input
$output = shell_exec("your_complex_shell_command " . $sanitized_input);

// Output the result
echo $output;