Authenticate using the Linux native method
Accepts two arguments

	1st) hex packed username e.g 6a6f65            produced as    echo -n joe      | xxd -ps
	2nd) hex packed password e.g 736f6d6570617373  produced as    echo -n somepass | xxd -ps

	./linux.sh 6a6f65 736f6d6570617373

It prints two lines

	1st)  0 for succesfull login  or a message of why the login was failed
	2nd)  A comma delimited group list, the user is member

e.g for success

	0
	joe,ftp,log,storage

or at failure

	Wrong password
	-

If you run this script as a non privilidge user you must add the user to sudoers e.g.
visudo

	# Defaults    requiretty

	dancer ALL=NOPASSWD: /usr/share/perl5/site_perl/Dancer2/Plugin/scripts/linux.sh

George Mpouras, george.mpouras@yandex.com, Athens Greece
 7 Jun 2016  Initial version
 9 Jul 2019  Clean up the code
