What are best practices for executing shell commands through a web server in PHP?

Executing shell commands through a web server in PHP can pose security risks if not done properly. To mitigate these risks, it is recommended to sanitize user input, use escapeshellarg() or escapeshellcmd() to escape command arguments, and limit the commands that can be executed to only necessary ones. 

// Sanitize user input
$command = filter_input(INPUT_POST, 'command', FILTER_SANITIZE_STRING);

// Escape command arguments
$escaped_command = escapeshellcmd($command);

// Limit commands to only necessary ones
$allowed_commands = ['ls', 'pwd', 'echo'];
if (in_array($escaped_command, $allowed_commands)) {
    // Execute the command
    $output = shell_exec($escaped_command);
    echo $output;
} else {
    echo "Command not allowed";
}

Keywords

shell commands web server PHP security escapeshellarg

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