%users = (
    rjt => {
        home  => '/home/rjt',
        uid   => 1000,
        shell => '/bin/bash',
        groups=> [ qw< sudo lpadmin > ],
    },
    jdlev => {
        home  => '/home/jdlev',
        uid   => 1001,
        shell => '/bin/csh',
        groups=> [ qw< users lpadmin > ],
    },
);
##</code><code>##

print "rjt's uid is $users{rjt}{uid}\n";

local $" = ', '; # List separator
print "jdlev is a member of: @{$users{jdlev}{groups}}.\n";

push @{$users{jdlev}{groups}}, 'sudo'; # jdlev now belongs to sudo as well