Using Chmod calculator you can generate permission quickly either in numerical or symbolic formats. Here you can generate the numerical or symbolic permission and copy past into any folder or file using Chmod command.
Change mode is shortly know as 'chmod' using this you can change the file or directory permission. Here you can use this for security purpose and give access for separate users also. Chmod permissions works on both UNIX and Linux systems.
Below you have an example to change file permission.chmod [options] [mode] [filename]
Example:chmod -R 775 index.php