sub check_passwd {
    my ($uname,$guess) = @_;
    my ($name, $passwd, $uid) = getpwnam($uname);
    $supervisor =  $uname;
    return (crypt($guess, $passwd) eq $passwd);
}
sub check_group {
    my ($uname,$group) = @_;
    while(($name, undef, undef, $members) = getgrent) {
        next if $name ne $group;
        return (grep { $_ eq $uname } split ( / /,$members )) ;
    }
}