NOTE: sh <file> and ./<file> are basically the same thing, but using ./ requires that the file permissions be executable (chmod +x <file>)
as far as the options, -aqn basically just speeds up the process by removing some of the questions the installer would normally make you answer.
Remember, you can almost always run <command> --help to get more info regarding options, in this case --help points you to --advanced-options for the complete list
Bypass the display and prompting for acceptance of the
NVIDIA Software License Agreement. By passing this option
to nvidia-installer, you indicate that you have read and
accept the License Agreement contained in the file
'LICENSE' (in the top level directory of the driver
Do not ask any questions; the default (normally 'yes') is
assumed for all yes/no questions, and the default string is
assumed in any situation where the user is prompted for
string input. The one question that is not bypassed by
this option is license acceptance; the license may be
accepted with the commandline option '--accept-license'.
Disable use of precompiled kernel interfaces.